diff --git a/CHANGELOG.md b/CHANGELOG.md
index e169ab646133..efd72adc6d04 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -16,9 +16,10 @@ All notable changes to this project will be documented in this file.
 
 * pin groups
   * added getter for lowest and highest index of pin group
-  * added column for pin index in pin tree shown in selection details
-  * added context menu entry to toggle between ascending and descending
-  * changed drag&drop behavior, allowing to drop pin on pin when ordering
+  * added column for pin index in GUI module pin tree
+  * added GUI module pin tree context menu entry to toggle between ascending and descending
+  * fixed GUI undo function for group delete
+  * changed GUI module pin tree drag'n drop behavior, allow drop pin(-group) on pin
    
 * fixed availability of "save as" so that does not required modifications to be enabaled
 * added feature to unzip and open hal project by dropping zipped file on welcome screen
diff --git a/plugins/gui/include/gui/basic_tree_model/base_tree_item.h b/plugins/gui/include/gui/basic_tree_model/base_tree_item.h
index 04df7bf683e5..048feec55c5d 100644
--- a/plugins/gui/include/gui/basic_tree_model/base_tree_item.h
+++ b/plugins/gui/include/gui/basic_tree_model/base_tree_item.h
@@ -87,7 +87,7 @@ namespace hal
          * @param index - The column to set the new data.
          * @param data - The new column data.
          */
-        virtual void setDataAtIndex(int index, QVariant& data) = 0;
+        virtual void setDataAtColumn(int column, QVariant& data) = 0;
 
         /**
          * Appends a new column to the item.
@@ -227,7 +227,7 @@ namespace hal
          * @param index - The column to set the new data.
          * @param data - The new column data.
          */
-        void setDataAtIndex(int index, QVariant& data) override;
+        void setDataAtColumn(int column, QVariant& data) override;
 
         /**
          * Appends a new column to the item.
diff --git a/plugins/gui/include/gui/context_manager_widget/models/context_tree_model.h b/plugins/gui/include/gui/context_manager_widget/models/context_tree_model.h
index fdc57eb783cf..632780c25f1d 100644
--- a/plugins/gui/include/gui/context_manager_widget/models/context_tree_model.h
+++ b/plugins/gui/include/gui/context_manager_widget/models/context_tree_model.h
@@ -71,7 +71,7 @@ namespace hal
             ContextTreeItem(ContextDirectory* directory);
             QVariant getData(int column) const override;
             void setData(QList<QVariant> data) override;
-            void setDataAtIndex(int index, QVariant& data) override;
+            void setDataAtColumn(int column, QVariant& data) override;
             void appendData(QVariant data) override;
             int getColumnCount() const override;
             int row() const;
diff --git a/plugins/gui/include/gui/gatelibrary_management/gatelibrary_tab_widgets/gatelibrary_tab_pin.h b/plugins/gui/include/gui/gatelibrary_management/gatelibrary_tab_widgets/gatelibrary_tab_pin.h
index 6c82f08361f4..96492ec10e3f 100644
--- a/plugins/gui/include/gui/gatelibrary_management/gatelibrary_tab_widgets/gatelibrary_tab_pin.h
+++ b/plugins/gui/include/gui/gatelibrary_management/gatelibrary_tab_widgets/gatelibrary_tab_pin.h
@@ -26,8 +26,6 @@
 #pragma once
 
 #include "gatelibrary_tab_interface.h"
-#include "gui/selection_details_widget/gate_details_widget/pin_tree_model.h"
-#include "hal_core/defines.h"
 #include "hal_core/netlist/gate_library/gate_type.h"
 
 #include <QGridLayout>
diff --git a/plugins/gui/include/gui/module_model/module_item.h b/plugins/gui/include/gui/module_model/module_item.h
index f7f84cfab3dc..95470d62143e 100644
--- a/plugins/gui/include/gui/module_model/module_item.h
+++ b/plugins/gui/include/gui/module_model/module_item.h
@@ -66,7 +66,7 @@ namespace hal
          * @param index - The column to set the new data. Either 0 (name) or 2(type). Other columns will be ignored.
          * @param data - The new column data.
          */
-        void setDataAtIndex(int index, QVariant& data) override;
+        void setDataAtColumn(int column, QVariant& data) override;
         /**
          * Unused dummy function overwritten from parent class.
          */
diff --git a/plugins/gui/include/gui/pin_model/pin_item.h b/plugins/gui/include/gui/pin_model/pin_item.h
index 16987b45270e..04e6d8b09305 100644
--- a/plugins/gui/include/gui/pin_model/pin_item.h
+++ b/plugins/gui/include/gui/pin_model/pin_item.h
@@ -50,7 +50,7 @@ namespace hal
         enum class TreeItemType {PinGroup, Pin, GroupCreator, PinCreator, InvalidPinGroup, InvalidPin};
 
         void setData(QList<QVariant> data) override;
-        void setDataAtIndex(int index, QVariant& data) override;
+        void setDataAtColumn(int column, QVariant& data) override;
         void appendData(QVariant data) override;
         int getColumnCount() const override;
 
diff --git a/plugins/gui/include/gui/selection_details_widget/gate_details_widget/gate_pin_tree.h b/plugins/gui/include/gui/selection_details_widget/gate_details_widget/gate_pin_tree.h
index 746eb58931e2..4a65590d37f7 100644
--- a/plugins/gui/include/gui/selection_details_widget/gate_details_widget/gate_pin_tree.h
+++ b/plugins/gui/include/gui/selection_details_widget/gate_details_widget/gate_pin_tree.h
@@ -33,7 +33,7 @@ namespace hal
 {
     class GatePinsTreeModel;
     class Gate;
-    class PinTreeItem;
+    class GatePinsTreeItem;
     class GraphNavigationWidget;
 
     /**
@@ -98,8 +98,8 @@ namespace hal
         bool mClearSelection;
 
         //helper functions
-        void buildPythonMenuForPin(QMenu &menu, PinTreeItem* clickedPinItem);
-        void buildPythonMenuForPinGroup(QMenu &menu, PinTreeItem* clickedPinIGrouptem);
+        void buildPythonMenuForPin(QMenu &menu, GatePinsTreeItem* clickedPinItem);
+        void buildPythonMenuForPinGroup(QMenu &menu, GatePinsTreeItem* clickedPinIGrouptem);
         void addSourceOurDestinationToSelection(int netId, bool isInputPin);
         void handleNavigationCloseRequested();
         void handleNavigationJumpRequested(const Node& origin, const u32 via_net, const QSet<u32>& to_gates, const QSet<u32>& to_modules);
diff --git a/plugins/gui/include/gui/selection_details_widget/gate_details_widget/pin_tree_model.h b/plugins/gui/include/gui/selection_details_widget/gate_details_widget/gate_pins_tree_model.h
similarity index 93%
rename from plugins/gui/include/gui/selection_details_widget/gate_details_widget/pin_tree_model.h
rename to plugins/gui/include/gui/selection_details_widget/gate_details_widget/gate_pins_tree_model.h
index e293a7ed820c..aabf65faaa20 100644
--- a/plugins/gui/include/gui/selection_details_widget/gate_details_widget/pin_tree_model.h
+++ b/plugins/gui/include/gui/selection_details_widget/gate_details_widget/gate_pins_tree_model.h
@@ -36,7 +36,7 @@ namespace hal
 
     class Gate;
 
-    class PinTreeItem : public BaseTreeItem
+    class GatePinsTreeItem : public BaseTreeItem
     {
     public:
         enum Type {None, Pin, Group};
@@ -51,11 +51,11 @@ namespace hal
             int mIndex;
         public:
 
-            PinTreeItem(const std::string& pinName, QString pinDirection, QString pinTypee, QString netName, int inx);
-            PinTreeItem();
+            GatePinsTreeItem(const std::string& pinName, QString pinDirection, QString pinTypee, QString netName, int inx);
+            GatePinsTreeItem();
             QVariant getData(int column) const override;
             void setData(QList<QVariant> data) override;
-            void setDataAtIndex(int index, QVariant& data) override;
+            void setDataAtColumn(int column, QVariant& data) override;
             void appendData(QVariant data) override;
             int getColumnCount() const override;
             void setType(Type tp) { mType = tp; }
diff --git a/plugins/gui/include/gui/selection_details_widget/module_details_widget/module_ports_tree.h b/plugins/gui/include/gui/selection_details_widget/module_details_widget/module_pins_tree.h
similarity index 100%
rename from plugins/gui/include/gui/selection_details_widget/module_details_widget/module_ports_tree.h
rename to plugins/gui/include/gui/selection_details_widget/module_details_widget/module_pins_tree.h
diff --git a/plugins/gui/include/gui/selection_details_widget/module_details_widget/port_tree_model.h b/plugins/gui/include/gui/selection_details_widget/module_details_widget/module_pins_tree_model.h
similarity index 85%
rename from plugins/gui/include/gui/selection_details_widget/module_details_widget/port_tree_model.h
rename to plugins/gui/include/gui/selection_details_widget/module_details_widget/module_pins_tree_model.h
index 1e1867e02307..fb5ce32162ef 100644
--- a/plugins/gui/include/gui/selection_details_widget/module_details_widget/port_tree_model.h
+++ b/plugins/gui/include/gui/selection_details_widget/module_details_widget/module_pins_tree_model.h
@@ -38,7 +38,7 @@ namespace hal
     class Net;
 
 
-    class PortTreeItem : public BaseTreeItem
+    class ModulePinsTreeItem : public BaseTreeItem
     {
     public:
         enum Type {None, Pin, Group};
@@ -54,11 +54,11 @@ namespace hal
 
         public:
 
-            PortTreeItem(Type itype, u32 id_, QString pinName, PinDirection dir, PinType ptype, int inx, QString netName = QString());
-            PortTreeItem() : mItemType(None), mId(0) {;}
+            ModulePinsTreeItem(Type itype, u32 id_, QString pinName, PinDirection dir, PinType ptype, int inx, QString netName = QString());
+            ModulePinsTreeItem() : mItemType(None), mId(0) {;}
             QVariant getData(int column) const override;
             void setData(QList<QVariant> data) override;
-            void setDataAtIndex(int index, QVariant& data) override;
+            void setDataAtColumn(int column, QVariant& data) override;
             void appendData(QVariant data) override;
             int getColumnCount() const override;
             void setItemType(Type tp) { mItemType = tp; }
@@ -127,7 +127,7 @@ namespace hal
          * @param item - The (port) item.
          * @return The net or nullptr.
          */
-        Net* getNetFromItem(PortTreeItem* item);
+        Net* getNetFromItem(ModulePinsTreeItem* item);
 
         /**
          * Get the id of the module that is currently represented.
@@ -162,18 +162,18 @@ namespace hal
         Module* mModule;
         //name is (hopefully) enough to identify
         QMap<QString, BaseTreeItem*> mNameToTreeItem;
-        QMap<int, PortTreeItem*> mIdToPinItem;
-        QMap<int, PortTreeItem*> mIdToGroupItem;
+        QMap<int, ModulePinsTreeItem*> mIdToPinItem;
+        QMap<int, ModulePinsTreeItem*> mIdToGroupItem;
 
-        void insertItem(PortTreeItem* item, BaseTreeItem* parent, int index);
-        void removeItem(PortTreeItem* item);
-        void updateGroupIndex(PortTreeItem* groupItem);
+        void insertItem(ModulePinsTreeItem* item, BaseTreeItem* parent, int index);
+        void removeItem(ModulePinsTreeItem* item);
+        void updateGroupIndex(ModulePinsTreeItem* groupItem);
 
         // helper functions for dnd for more clarity
         void dndGroupOnGroup(BaseTreeItem* droppedGroup, BaseTreeItem* onDroppedGroup, int row=-1);
-        void dndGroupBetweenGroup(PortTreeItem* droppedGroup, int row);
-        void dndPinOnGroup(PortTreeItem* droppedPin, BaseTreeItem* onDroppedGroup);
-        void dndPinBetweenPin(PortTreeItem* droppedPin, BaseTreeItem* onDroppedParent, int row);
-        void dndPinBetweenGroup(PortTreeItem* droppedPin, int row);
+        void dndGroupBetweenGroup(ModulePinsTreeItem* droppedGroup, int row);
+        void dndPinOnGroup(ModulePinsTreeItem* droppedPin, BaseTreeItem* onDroppedGroup);
+        void dndPinBetweenPin(ModulePinsTreeItem* droppedPin, BaseTreeItem* onDroppedParent, int row);
+        void dndPinBetweenGroup(ModulePinsTreeItem* droppedPin, int row);
     };
 }
diff --git a/plugins/gui/include/gui/user_action/action_pingroup.h b/plugins/gui/include/gui/user_action/action_pingroup.h
index 29b1ebdf6314..67470e543ddb 100644
--- a/plugins/gui/include/gui/user_action/action_pingroup.h
+++ b/plugins/gui/include/gui/user_action/action_pingroup.h
@@ -46,14 +46,6 @@ namespace hal
         static bool useExistingPin(Type tp);
     };
 
-    int pinGroupIndex(const Module* mod, const PinGroup<ModulePin>* pgrp);
-
-    int pinIndex2Row(const ModulePin* pin, int index);
-
-    int pinRow2Index(const ModulePin* pin, int row);
-
-    QString generateGroupName(const Module* mod, const ModulePin* pin);
-
     void dumpPingroups(Module* m = nullptr);
     /**
      * @ingroup user_action
@@ -66,8 +58,7 @@ namespace hal
      *                   negative ID: call constructor without ID, however,
      *                   ID will be used internally for subsequent commands related to crated group
      *     name     : name of group
-     *     value    : start index, assume ascending
-     *                   negative value: descending order starting with (-value-1)
+     *     value    : start index * 2, LSB : 0=descending 1=ascending
      *
      * GroupDelete
      *     ID       : ID of group to delete
@@ -135,6 +126,7 @@ namespace hal
 
         QHash<int,PinGroup<ModulePin>*> mPinGroups;
         QList<AtomicAction> mPinActions;
+        QList<QList<AtomicAction> > mTempUndoActions;
         Module* mParentModule;
         QMap<int,GroupRestore> mGroupRestore;
         QSet<u32> mPinsMoved;
@@ -144,7 +136,6 @@ namespace hal
         PinGroup<ModulePin>* getGroup(int grpId) const;
         void prepareUndoAction();
         void finalizeUndoAction();
-        void addUndoAction(PinActionType::Type tp, int id = 0, const QString& name=QString(), int value=0);
         static int pinGroupRow(const Module *m, PinGroup<ModulePin>* pgroup);
     public:
         ActionPingroup(PinActionType::Type tp = PinActionType::None, int id = 0, const QString& name=QString(), int value=0);
@@ -163,6 +154,11 @@ namespace hal
         static ActionPingroup* deletePinGroup(const Module* m, u32 grpId);
         static ActionPingroup* toggleAscendingGroup(const Module* m, u32 grpId);
         static ActionPingroup* changePinGroupType(const Module* m, u32 grpId, int ptype);
+
+        static int pinGroupIndex(const Module* mod, const PinGroup<ModulePin>* pgrp);
+        static int pinIndex2Row(const ModulePin* pin, int index);
+        static int pinRow2Index(const ModulePin* pin, int row);
+        static QString generateGroupName(const Module* mod, const ModulePin* pin);
     };
 
     /**
diff --git a/plugins/gui/src/basic_tree_model/base_tree_item.cpp b/plugins/gui/src/basic_tree_model/base_tree_item.cpp
index 17bc9a78d64c..2d7aad398509 100644
--- a/plugins/gui/src/basic_tree_model/base_tree_item.cpp
+++ b/plugins/gui/src/basic_tree_model/base_tree_item.cpp
@@ -114,11 +114,11 @@ namespace hal
         }
     }
 
-    void RootTreeItem::setDataAtIndex(int index, QVariant &data)
+    void RootTreeItem::setDataAtColumn(int column, QVariant &data)
     {
-        while (index >= mHeaderLabels.size())
+        while (column >= mHeaderLabels.size())
             mHeaderLabels << QString();
-        mHeaderLabels[index] = data.toString();
+        mHeaderLabels[column] = data.toString();
     }
 
     void RootTreeItem::appendData(QVariant data)
diff --git a/plugins/gui/src/basic_tree_model/base_tree_model.cpp b/plugins/gui/src/basic_tree_model/base_tree_model.cpp
index 9066ac917f31..1292f6a31ab3 100644
--- a/plugins/gui/src/basic_tree_model/base_tree_model.cpp
+++ b/plugins/gui/src/basic_tree_model/base_tree_model.cpp
@@ -114,7 +114,7 @@ namespace hal
         else
             for (int i=0; i<labels.size(); i++) {
                 QVariant qv = QVariant(labels.at(i));
-                mRootItem->setDataAtIndex(i, qv);
+                mRootItem->setDataAtColumn(i, qv);
             }
 
 
diff --git a/plugins/gui/src/context_manager_widget/models/context_tree_model.cpp b/plugins/gui/src/context_manager_widget/models/context_tree_model.cpp
index a6c67300c199..38a4e94476d8 100644
--- a/plugins/gui/src/context_manager_widget/models/context_tree_model.cpp
+++ b/plugins/gui/src/context_manager_widget/models/context_tree_model.cpp
@@ -94,9 +94,9 @@ namespace hal
 
     }
 
-    void ContextTreeItem::setDataAtIndex(int index, QVariant &data)
+    void ContextTreeItem::setDataAtColumn(int column, QVariant &data)
     {
-
+        // TODO: implement
     }
 
     void ContextTreeItem::appendData(QVariant data)
diff --git a/plugins/gui/src/module_model/module_item.cpp b/plugins/gui/src/module_model/module_item.cpp
index 9fadba89b7c5..f4a196a1e65e 100644
--- a/plugins/gui/src/module_model/module_item.cpp
+++ b/plugins/gui/src/module_model/module_item.cpp
@@ -106,9 +106,9 @@ ModuleItem::ModuleItem(const u32 id, const TreeItemType type, ModuleModel *model
             setModuleType(data.at(2).toString());
     }
 
-    void ModuleItem::setDataAtIndex(int index, QVariant &data)
+    void ModuleItem::setDataAtColumn(int column, QVariant &data)
     {
-        switch (index) {
+        switch (column) {
         case 0:
             setName(data.toString());
             return;
diff --git a/plugins/gui/src/pin_model/pin_item.cpp b/plugins/gui/src/pin_model/pin_item.cpp
index 2397626293d1..b6f2fb9d743f 100644
--- a/plugins/gui/src/pin_model/pin_item.cpp
+++ b/plugins/gui/src/pin_model/pin_item.cpp
@@ -73,9 +73,9 @@ namespace hal
         mId = newId;
     }
 
-    void PinItem::setDataAtIndex(int index, QVariant &data)
+    void PinItem::setDataAtColumn(int column, QVariant &data)
     {
-
+        // TODO : implement ?!
     }
 
     QString PinItem::getName() const
diff --git a/plugins/gui/src/selection_details_widget/gate_details_widget/gate_pin_tree.cpp b/plugins/gui/src/selection_details_widget/gate_details_widget/gate_pin_tree.cpp
index 754770955ef8..7acd400108c9 100644
--- a/plugins/gui/src/selection_details_widget/gate_details_widget/gate_pin_tree.cpp
+++ b/plugins/gui/src/selection_details_widget/gate_details_widget/gate_pin_tree.cpp
@@ -1,5 +1,5 @@
 #include "gui/selection_details_widget/gate_details_widget/gate_pin_tree.h"
-#include "gui/selection_details_widget/gate_details_widget/pin_tree_model.h"
+#include "gui/selection_details_widget/gate_details_widget/gate_pins_tree_model.h"
 //#include "gui/gui_globals.h"
 #include "hal_core/netlist/gate.h"
 #include <QHeaderView>
@@ -69,8 +69,8 @@ namespace hal
         if(!idx.isValid())
             return;
 
-        PinTreeItem* clickedItem = dynamic_cast<PinTreeItem*>(mPinModel->getItemFromIndex(idx));
-        if(!clickedItem || clickedItem->type() != PinTreeItem::Pin)
+        GatePinsTreeItem* clickedItem = dynamic_cast<GatePinsTreeItem*>(mPinModel->getItemFromIndex(idx));
+        if(!clickedItem || clickedItem->type() != GatePinsTreeItem::Pin)
             return;
 
         auto netId = clickedItem->netIds().front();
@@ -96,7 +96,7 @@ namespace hal
         if(!idx.isValid())
             return;
 
-        PinTreeItem* clickedItem = dynamic_cast<PinTreeItem*>(mPinModel->getItemFromIndex(idx));
+        GatePinsTreeItem* clickedItem = dynamic_cast<GatePinsTreeItem*>(mPinModel->getItemFromIndex(idx));
         QMenu menu;
         bool isMiscSectionSet = false;//so that the misc-section is not set multiple times
 
@@ -117,7 +117,7 @@ namespace hal
         });
 
         //Check if jump to source or destination is possible
-        if(clickedItem->type() == PinTreeItem::Pin && clickedItem->netIds().size()==1)
+        if(clickedItem->type() == GatePinsTreeItem::Pin && clickedItem->netIds().size()==1)
         {
             auto netId = clickedItem->netIds().front();
             auto clickedNet = gNetlist->get_net_by_id(netId);
@@ -156,7 +156,7 @@ namespace hal
 
         //Add nets to selection if possible
         QList<u32> netIds;
-        if(clickedItem->type() == PinTreeItem::Pin)
+        if(clickedItem->type() == GatePinsTreeItem::Pin)
         {
             netIds = clickedItem->netIds();
         }
@@ -164,7 +164,7 @@ namespace hal
         {
             for(auto childItem : clickedItem->getChildren())
             {
-                PinTreeItem* pti = dynamic_cast<PinTreeItem*>(childItem);
+                GatePinsTreeItem* pti = dynamic_cast<GatePinsTreeItem*>(childItem);
                 if (pti)
                     netIds.append(pti->netIds());
             }
@@ -194,7 +194,7 @@ namespace hal
 
         menu.addSection("Python");
 
-        if(clickedItem->type() == PinTreeItem::Pin)
+        if(clickedItem->type() == GatePinsTreeItem::Pin)
             buildPythonMenuForPin(menu, clickedItem);
         else
             buildPythonMenuForPinGroup(menu, clickedItem);
@@ -204,7 +204,7 @@ namespace hal
 
     }
 
-    void GatePinTree::buildPythonMenuForPin(QMenu &menu, PinTreeItem *clickedPinItem)
+    void GatePinTree::buildPythonMenuForPin(QMenu &menu, GatePinsTreeItem *clickedPinItem)
     {
         // 1.) NET-OBJECT
         QList<u32> netIdsOfItem = clickedPinItem->netIds();
@@ -246,7 +246,7 @@ namespace hal
 
     }
 
-    void GatePinTree::buildPythonMenuForPinGroup(QMenu &menu, PinTreeItem *clickedPinIGrouptem)
+    void GatePinTree::buildPythonMenuForPinGroup(QMenu &menu, GatePinsTreeItem *clickedPinIGrouptem)
     {
         // 1. PYTHON LIST OF PIN GROUPS
         QString pythonList = "[";
diff --git a/plugins/gui/src/selection_details_widget/gate_details_widget/pin_tree_model.cpp b/plugins/gui/src/selection_details_widget/gate_details_widget/gate_pins_tree_model.cpp
similarity index 85%
rename from plugins/gui/src/selection_details_widget/gate_details_widget/pin_tree_model.cpp
rename to plugins/gui/src/selection_details_widget/gate_details_widget/gate_pins_tree_model.cpp
index bde590548815..5fe6c5e021fb 100644
--- a/plugins/gui/src/selection_details_widget/gate_details_widget/pin_tree_model.cpp
+++ b/plugins/gui/src/selection_details_widget/gate_details_widget/gate_pins_tree_model.cpp
@@ -1,10 +1,9 @@
-#include "gui/selection_details_widget/gate_details_widget/pin_tree_model.h"
+#include "gui/selection_details_widget/gate_details_widget/gate_pins_tree_model.h"
 
 #include "gui/gui_globals.h"
 #include "hal_core/netlist/gate.h"
 #include "hal_core/netlist/gate_library/gate_type.h"
 #include "hal_core/netlist/net.h"
-#include "hal_core/utilities/enums.h"
 
 #include <QDebug>
 #include <QVector>
@@ -12,14 +11,14 @@
 namespace hal
 {
 
-    PinTreeItem::PinTreeItem(const std::string &pinName, QString pinDirection, QString pinType, QString netName, int inx)
+    GatePinsTreeItem::GatePinsTreeItem(const std::string &pinName, QString pinDirection, QString pinType, QString netName, int inx)
         :mPinName(pinName), mPinDirection(pinDirection), mPinType(pinType), mNetName(netName), mIndex(inx)
     {;}
 
-    PinTreeItem::PinTreeItem()
+    GatePinsTreeItem::GatePinsTreeItem()
     {;}
 
-    QVariant PinTreeItem::getData(int index) const
+    QVariant GatePinsTreeItem::getData(int index) const
     {
         switch (index)
         {
@@ -32,14 +31,14 @@ namespace hal
         case 3:
             return mNetName;
         case 4:
-            if (mType == PinTreeItem::Group)
+            if (mType == GatePinsTreeItem::Group)
                 return (mIndex ? "descending" : "ascending");
             return mIndex;
         }
         return QVariant();
     }
 
-    void PinTreeItem::setData(QList<QVariant> data)
+    void GatePinsTreeItem::setData(QList<QVariant> data)
     {
         Q_ASSERT(data.size() >= 5);
         mPinName = data[0].toString().toStdString();
@@ -49,9 +48,9 @@ namespace hal
         mIndex = data[4].toInt();
     }
 
-    void PinTreeItem::setDataAtIndex(int index, QVariant &data)
+    void GatePinsTreeItem::setDataAtColumn(int column, QVariant &data)
     {
-        switch (index)
+        switch (column)
         {
         case 0:
             mPinName = data.toString().toStdString();
@@ -73,9 +72,9 @@ namespace hal
 
     }
 
-    void PinTreeItem::appendData(QVariant data) {}
+    void GatePinsTreeItem::appendData(QVariant data) {}
 
-    int PinTreeItem::getColumnCount() const
+    int GatePinsTreeItem::getColumnCount() const
     {
         return 5;
     }
@@ -114,7 +113,7 @@ namespace hal
         GateType* gateType = g->get_type();
         for (auto pin : gateType->get_pins())
         {
-            PinTreeItem* pinItem = new PinTreeItem();
+            GatePinsTreeItem* pinItem = new GatePinsTreeItem();
             //get all infos for that pin
             const PinGroup<GatePin>* pg = pin->get_group().first;
             const std::string& grpName  = pg->get_name();
@@ -164,16 +163,16 @@ namespace hal
             }
 
             pinItem->setData(QList<QVariant>() << QString::fromStdString(pin->get_name()) << pinDirection << pinType << netName << inx);
-            pinItem->setType(PinTreeItem::Pin);
+            pinItem->setType(GatePinsTreeItem::Pin);
             pinItem->setNetIds(netIDs);
             if (!grpName.empty())
             {
-                PinTreeItem* pingroupItem = dynamic_cast<PinTreeItem*>(mPinGroupToTreeItem.value(grpName, nullptr));    //since its a map, its okay
+                GatePinsTreeItem* pingroupItem = dynamic_cast<GatePinsTreeItem*>(mPinGroupToTreeItem.value(grpName, nullptr));    //since its a map, its okay
                 if (!pingroupItem)
                 {
                     //assume all items in the same grouping habe the same direction and type, so the grouping-item has also these types
-                    pingroupItem = new PinTreeItem(grpName, pinDirection, pinType, "", iDescending);
-                    pingroupItem->setType(PinTreeItem::Group);
+                    pingroupItem = new GatePinsTreeItem(grpName, pinDirection, pinType, "", iDescending);
+                    pingroupItem->setType(GatePinsTreeItem::Group);
                     mRootItem->appendChild(pingroupItem);
                     mPinGroupToTreeItem.insert(grpName, pingroupItem);
                 }
diff --git a/plugins/gui/src/selection_details_widget/module_details_tab_widget.cpp b/plugins/gui/src/selection_details_widget/module_details_tab_widget.cpp
index bf04ac128067..94e133776ffa 100644
--- a/plugins/gui/src/selection_details_widget/module_details_tab_widget.cpp
+++ b/plugins/gui/src/selection_details_widget/module_details_tab_widget.cpp
@@ -2,7 +2,7 @@
 
 #include "gui/selection_details_widget/details_frame_widget.h"
 #include "gui/selection_details_widget/module_details_widget/module_info_table.h"
-#include "gui/selection_details_widget/module_details_widget/module_ports_tree.h"
+#include "gui/selection_details_widget/module_details_widget/module_pins_tree.h"
 #include "gui/selection_details_widget/module_details_widget/module_elements_tree.h"
 #include "gui/comment_system/widgets/comment_widget.h"
 
diff --git a/plugins/gui/src/selection_details_widget/module_details_widget/module_ports_tree.cpp b/plugins/gui/src/selection_details_widget/module_details_widget/module_pins_tree.cpp
similarity index 93%
rename from plugins/gui/src/selection_details_widget/module_details_widget/module_ports_tree.cpp
rename to plugins/gui/src/selection_details_widget/module_details_widget/module_pins_tree.cpp
index dd23d18070cd..f4872f86f04f 100644
--- a/plugins/gui/src/selection_details_widget/module_details_widget/module_ports_tree.cpp
+++ b/plugins/gui/src/selection_details_widget/module_details_widget/module_pins_tree.cpp
@@ -1,11 +1,11 @@
-#include "gui/selection_details_widget/module_details_widget/module_ports_tree.h"
+#include "gui/selection_details_widget/module_details_widget/module_pins_tree.h"
 
 #include "gui/gui_globals.h"
 #include "gui/input_dialog/combobox_dialog.h"
 #include "gui/input_dialog/input_dialog.h"
 #include "gui/input_dialog/pingroup_selector_dialog.h"
 #include "gui/python/py_code_provider.h"
-#include "gui/selection_details_widget/module_details_widget/port_tree_model.h"
+#include "gui/selection_details_widget/module_details_widget/module_pins_tree_model.h"
 #include "gui/user_action/action_pingroup.h"
 #include "hal_core/netlist/gate_library/enums/pin_type.h"
 #include "hal_core/utilities/enums.h"
@@ -81,7 +81,7 @@ namespace hal
             return;
 
         //all relevant information
-        PortTreeItem* clickedItem          =  static_cast<PortTreeItem*>(mPortModel->getItemFromIndex(clickedIndex));
+        ModulePinsTreeItem* clickedItem          =  static_cast<ModulePinsTreeItem*>(mPortModel->getItemFromIndex(clickedIndex));
         Net* n                             = mPortModel->getNetFromItem(clickedItem);
         QString name                       = clickedItem->getData(ModulePinsTreeModel::sNameColumn).toString();
         u32 modId                          = mPortModel->getRepresentedModuleId();
@@ -122,7 +122,7 @@ namespace hal
                         return;
                     for (auto item : selectedPins)
                     {
-                        auto* pin = mod->get_pin_by_id(static_cast<PortTreeItem*>(item)->id());
+                        auto* pin = mod->get_pin_by_id(static_cast<ModulePinsTreeItem*>(item)->id());
                         if (pin == nullptr)
                             return;
                         pins.append(pin->get_id());
@@ -133,7 +133,7 @@ namespace hal
             });
         }
 
-        if (clickedItem->itemType() == PortTreeItem::Group)    //group specific context, own helper function? (returns at the end)
+        if (clickedItem->itemType() == ModulePinsTreeItem::Group)    //group specific context, own helper function? (returns at the end)
         {
             menu.addAction("Change name", [itemId, mod, name]() {
                 PinGroup<ModulePin>*  pg = mod->get_pin_group_by_id(itemId);
@@ -246,7 +246,7 @@ namespace hal
             menu.addAction("Remove selection from group", [selectedPins, mod /*, sameGroup*/]() {
                 QList<u32> pins;
                 for (auto item : selectedPins)
-                    pins.append(static_cast<PortTreeItem*>(item)->id());
+                    pins.append(static_cast<ModulePinsTreeItem*>(item)->id());
 
                 ActionPingroup* act = ActionPingroup::removePinsFromGroup(mod, pins);
                 if (act) act->exec();
@@ -258,7 +258,7 @@ namespace hal
             appendMultiSelectionEntries(menu, modId);
 
         menu.addSection("Python");
-        if(clickedItem->itemType()==PortTreeItem::Pin)
+        if(clickedItem->itemType()==ModulePinsTreeItem::Pin)
             menu.addAction(QIcon(":/icons/python"), "Get pin", [modId, itemId]() { QApplication::clipboard()->setText(PyCodeProvider::pyCodeModulePinById(modId, itemId)); });
         else
             menu.addAction(QIcon(":/icons/python"), "Get group", [modId, itemId]() { QApplication::clipboard()->setText(PyCodeProvider::pyCodeModulePinGroup(modId, itemId)); });
@@ -288,7 +288,7 @@ namespace hal
                     Module* mod = gNetlist->get_module_by_id(modId);
                     for (auto item : selectedPins)
                     {
-                        auto* pin = mod->get_pin_by_id(static_cast<PortTreeItem*>(item)->id());
+                        auto* pin = mod->get_pin_by_id(static_cast<ModulePinsTreeItem*>(item)->id());
                         if (pin == nullptr)
                             return;
                         pins.append(pin->get_id());
@@ -310,8 +310,8 @@ namespace hal
         int groupId    = -1;
         for (auto index : selectionModel()->selectedRows())
         {
-            PortTreeItem* item =  static_cast<PortTreeItem*>(mPortModel->getItemFromIndex(index));
-            if (item->itemType() == PortTreeItem::Pin)
+            ModulePinsTreeItem* item =  static_cast<ModulePinsTreeItem*>(mPortModel->getItemFromIndex(index));
+            if (item->itemType() == ModulePinsTreeItem::Pin)
             {
                 if (!alreadyProcessedPins.contains(item))
                 {
@@ -319,7 +319,7 @@ namespace hal
                     alreadyProcessedPins.insert(item);
                 }
             }
-            else if (item->itemType() == PortTreeItem::Group)
+            else if (item->itemType() == ModulePinsTreeItem::Group)
             {
                 onlyPins = false;
                 for (auto pinItem : item->getChildren())
@@ -336,11 +336,11 @@ namespace hal
         if (!selectedPins.isEmpty())
         {
             auto mod       = gNetlist->get_module_by_id(mModuleID);
-            auto* firstPin = mod->get_pin_by_id(static_cast<PortTreeItem*>(selectedPins.front())->id());
+            auto* firstPin = mod->get_pin_by_id(static_cast<ModulePinsTreeItem*>(selectedPins.front())->id());
             groupId        = firstPin->get_group().first->get_id();
             for (auto pinTreeItem : selectedPins)
             {
-                auto pin = mod->get_pin_by_id(static_cast<PortTreeItem*>(pinTreeItem)->id());
+                auto pin = mod->get_pin_by_id(static_cast<ModulePinsTreeItem*>(pinTreeItem)->id());
                 if (groupId != (int)pin->get_group().first->get_id())
                 {
                     sameGroup = false;
diff --git a/plugins/gui/src/selection_details_widget/module_details_widget/port_tree_model.cpp b/plugins/gui/src/selection_details_widget/module_details_widget/module_pins_tree_model.cpp
similarity index 83%
rename from plugins/gui/src/selection_details_widget/module_details_widget/port_tree_model.cpp
rename to plugins/gui/src/selection_details_widget/module_details_widget/module_pins_tree_model.cpp
index 7dd546b13851..202ec24693c0 100644
--- a/plugins/gui/src/selection_details_widget/module_details_widget/port_tree_model.cpp
+++ b/plugins/gui/src/selection_details_widget/module_details_widget/module_pins_tree_model.cpp
@@ -1,4 +1,4 @@
-#include "gui/selection_details_widget/module_details_widget/port_tree_model.h"
+#include "gui/selection_details_widget/module_details_widget/module_pins_tree_model.h"
 
 #include "gui/basic_tree_model/base_tree_item.h"
 #include "gui/gui_globals.h"
@@ -15,11 +15,11 @@
 
 namespace hal
 {
-    PortTreeItem::PortTreeItem(Type itype, u32 id_, QString pinName, PinDirection dir, PinType ptype, int inx, QString netName)
+    ModulePinsTreeItem::ModulePinsTreeItem(Type itype, u32 id_, QString pinName, PinDirection dir, PinType ptype, int inx, QString netName)
         : mItemType(itype), mId(id_), mPinName(pinName), mPinDirection(dir), mPinType(ptype), mNetName(netName), mIndex(inx)
     {;}
 
-    QVariant PortTreeItem::getData(int index) const
+    QVariant ModulePinsTreeItem::getData(int index) const
     {
         switch (index)
         {
@@ -32,14 +32,14 @@ namespace hal
         case 3:
             return mNetName;
         case 4:
-            if (mItemType==PortTreeItem::Group)
+            if (mItemType==ModulePinsTreeItem::Group)
                 return ( mIndex ? "descending" : "ascending");
             return mIndex;
         }
         return QVariant();
     }
 
-    void PortTreeItem::setData(QList<QVariant> data)
+    void ModulePinsTreeItem::setData(QList<QVariant> data)
     {
         Q_ASSERT(data.size() >= 5);
         mPinName      = data[0].toString();
@@ -49,9 +49,9 @@ namespace hal
         mIndex        = data[4].toInt();
     }
 
-    void PortTreeItem::setDataAtIndex(int index, QVariant &data)
+    void ModulePinsTreeItem::setDataAtColumn(int column, QVariant &data)
     {
-        switch (index)
+        switch (column)
         {
         case 0:
             mPinName = data.toString();
@@ -71,12 +71,12 @@ namespace hal
         }
     }
 
-    void PortTreeItem::appendData(QVariant data)
+    void ModulePinsTreeItem::appendData(QVariant data)
     {
         Q_UNUSED(data)
     }
 
-    int PortTreeItem::getColumnCount() const
+    int ModulePinsTreeItem::getColumnCount() const
     {
         return 5;
     }
@@ -142,12 +142,12 @@ namespace hal
             return new QMimeData();
 
         QMimeData* data = new QMimeData();
-        PortTreeItem* item = static_cast<PortTreeItem*>(getItemFromIndex(indexes.at(0)));
+        ModulePinsTreeItem* item = static_cast<ModulePinsTreeItem*>(getItemFromIndex(indexes.at(0)));
         QByteArray encodedData;
         QDataStream stream(&encodedData, QIODevice::WriteOnly);
-        QString type = item->itemType() == PortTreeItem::Pin ? "pin" : "group";
+        QString type = item->itemType() == ModulePinsTreeItem::Pin ? "pin" : "group";
         stream << type << item->id();
-        data->setText(item->itemType() == PortTreeItem::Pin
+        data->setText(item->itemType() == ModulePinsTreeItem::Pin
                         ? PyCodeProvider::pyCodeModulePinById(mModule->get_id(),item->id())
                         : PyCodeProvider::pyCodeModulePinGroup(mModule->get_id(),item->id()));
         data->setData("pintreemodel/item", encodedData);
@@ -166,7 +166,7 @@ namespace hal
 // debug pingroup        qDebug() << "dropMimeData" << encItem << row << column;
         dataStream >> type >> id;
 
-        auto droppedItem = (type == "group") ?  static_cast<PortTreeItem*>(mIdToGroupItem.value(id)) :  static_cast<PortTreeItem*>(mIdToPinItem.value(id));
+        auto droppedItem = (type == "group") ?  static_cast<ModulePinsTreeItem*>(mIdToGroupItem.value(id)) :  static_cast<ModulePinsTreeItem*>(mIdToPinItem.value(id));
         //auto droppedParentItem = droppedItem->getParent();
         auto dropPositionItem = getItemFromIndex(parent);
 
@@ -187,11 +187,11 @@ namespace hal
             }
             else
             {
-                PortTreeItem* pitem = dynamic_cast<PortTreeItem*>(dropPositionItem);
-                if (pitem && pitem->itemType() == PortTreeItem::Pin)
+                ModulePinsTreeItem* pitem = dynamic_cast<ModulePinsTreeItem*>(dropPositionItem);
+                if (pitem && pitem->itemType() == ModulePinsTreeItem::Pin)
                 {
                     // debug pingroup                qDebug() << "group was dropped on a pin...";
-                    PortTreeItem* parentGroupItem = static_cast<PortTreeItem*>(pitem->getParent());
+                    ModulePinsTreeItem* parentGroupItem = static_cast<ModulePinsTreeItem*>(pitem->getParent());
                     row = getIndexFromItem(pitem).row();
                     dndGroupOnGroup(droppedItem, parentGroupItem, row);
                 }
@@ -214,11 +214,11 @@ namespace hal
             }
             else
             {
-                PortTreeItem* pitem = dynamic_cast<PortTreeItem*>(dropPositionItem);
-                if (pitem && pitem->itemType() == PortTreeItem::Pin)
+                ModulePinsTreeItem* pitem = dynamic_cast<ModulePinsTreeItem*>(dropPositionItem);
+                if (pitem && pitem->itemType() == ModulePinsTreeItem::Pin)
                 {
 // debug pingroup                qDebug() << "pin was dropped on a pin...";
-                    PortTreeItem* parentGroupItem = static_cast<PortTreeItem*>(pitem->getParent());
+                    ModulePinsTreeItem* parentGroupItem = static_cast<ModulePinsTreeItem*>(pitem->getParent());
                     row = getIndexFromItem(pitem).row();
                     dndPinBetweenPin(droppedItem, parentGroupItem, row);
                 }
@@ -242,7 +242,7 @@ namespace hal
         auto encItem = data->data("pintreemodel/item");
         QDataStream dataStream(&encItem, QIODevice::ReadOnly);
         dataStream >> type >> id;
-        auto parentItem = static_cast<PortTreeItem*>(getItemFromIndex(parent));
+        auto parentItem = static_cast<ModulePinsTreeItem*>(getItemFromIndex(parent));
      //   qDebug() << "type: " << type << ", id" << id << ", row: " << row;
 
         // construct a "drop-matrix" here, but only 4(5) things are NOT allowed (so check for these):
@@ -252,10 +252,10 @@ namespace hal
         // 5: drop adjecent index to itself, must be at least 1 item apart
         if(type == "group")
         {
-            auto item = static_cast<PortTreeItem*>(mIdToGroupItem[id]);
+            auto item = static_cast<ModulePinsTreeItem*>(mIdToGroupItem[id]);
             if(parentItem)
             {
-                if(item->itemType() == PortTreeItem::Pin || (item->itemType() == PortTreeItem::Group && row != -1) || item == parentItem)
+                if(item->itemType() == ModulePinsTreeItem::Pin || (item->itemType() == ModulePinsTreeItem::Group && row != -1) || item == parentItem)
                     return false;
             }
             else // here, only check for adjacent rows
@@ -306,12 +306,12 @@ namespace hal
                 continue;
 
             auto pinGroupName = QString::fromStdString(pinGroup->get_name());
-            PortTreeItem* pinGroupItem = new PortTreeItem(PortTreeItem::Group, pinGroup->get_id(), pinGroupName, pinGroup->get_direction(),
+            ModulePinsTreeItem* pinGroupItem = new ModulePinsTreeItem(ModulePinsTreeItem::Group, pinGroup->get_id(), pinGroupName, pinGroup->get_direction(),
                                                           pinGroup->get_type(), pinGroup->is_ascending() ? 0 : 1);
             mIdToGroupItem.insert(pinGroup->get_id(), pinGroupItem);
             for(ModulePin* pin : pinGroup->get_pins())
             {
-                PortTreeItem* pinItem = new PortTreeItem(PortTreeItem::Pin,
+                ModulePinsTreeItem* pinItem = new ModulePinsTreeItem(ModulePinsTreeItem::Pin,
                                                          pin->get_id(),
                                                          QString::fromStdString(pin->get_name()),
                                                          pin->get_direction(),
@@ -326,6 +326,8 @@ namespace hal
             mRootItem->appendChild(pinGroupItem);
         }
 
+//        Keep old code for the time being to review whether all cases are covered
+//
 //        for (PinGroup<ModulePin>* pinGroup : m->get_pin_groups())
 //        {
 //            //ignore empty pingroups
@@ -350,7 +352,7 @@ namespace hal
 
 //            if (pinGroup->size() == 1)
 //            {
-//                pinGroupItem->setDataAtIndex(sNetColumn, QString::fromStdString(firstPin->get_net()->get_name()));
+//                pinGroupItem->setDataAtColumn(sNetColumn, QString::fromStdString(firstPin->get_net()->get_name()));
 //                pinGroupItem->setAdditionalData(keyType, QVariant::fromValue(itemType::pin));
 //                //since a single-pin pingroup represents the pin itself, take the pinid
 //                pinGroupItem->setAdditionalData(keyId, firstPin->get_id());
@@ -380,12 +382,12 @@ namespace hal
         Q_EMIT numberOfPortsChanged(m->get_pins().size());
     }
 
-    Net* ModulePinsTreeModel::getNetFromItem(PortTreeItem* item)
+    Net* ModulePinsTreeModel::getNetFromItem(ModulePinsTreeItem* item)
     {
         if (!mModule)    //no current module = no represented net
             return nullptr;
 
-        if (item->itemType() == PortTreeItem::Group && item->getChildCount() > 1)
+        if (item->itemType() == ModulePinsTreeItem::Group && item->getChildCount() > 1)
             return nullptr;
 
         Module* m = gNetlist->get_module_by_id(mModule->get_id());
@@ -420,8 +422,8 @@ namespace hal
         if (m != mModule) return;
 
         // debug pingroups  log_info("gui", "Handle pin_changed event {} ID={}", enum_to_string<PinEvent>(pev), pgid);
-        PortTreeItem* ptiPin = nullptr;
-        PortTreeItem* ptiGroup = nullptr;
+        ModulePinsTreeItem* ptiPin = nullptr;
+        ModulePinsTreeItem* ptiGroup = nullptr;
         const PinGroup<ModulePin>* pgroup = nullptr;
         const ModulePin* pin = nullptr;
         int pinRow = -1;
@@ -465,7 +467,7 @@ namespace hal
                 }
                 auto pgPair = pin->get_group();
                 pgroup = pgPair.first;
-                pinRow = pinIndex2Row(pin,pgPair.second);
+                pinRow = ActionPingroup::pinIndex2Row(pin,pgPair.second);
                 if (pgroup)
                     ptiGroup = mIdToGroupItem.value(pgroup->get_id());
             }
@@ -477,20 +479,20 @@ namespace hal
         {
         case PinEvent::GroupCreate:
         {
-            ptiGroup = new PortTreeItem(PortTreeItem::Group,
+            ptiGroup = new ModulePinsTreeItem(ModulePinsTreeItem::Group,
                                         pgroup->get_id(),
                                     QString::fromStdString(pgroup->get_name()),
                                     pgroup->get_direction(),
                                     pgroup->get_type(),
                                     pgroup->is_ascending()?0:1);
             mIdToGroupItem.insert(ptiGroup->id(), ptiGroup);
-            int inx = pinGroupIndex(m,pgroup);
+            int inx = ActionPingroup::pinGroupIndex(m,pgroup);
             insertItem(ptiGroup, mRootItem, inx);
             break;
         }
         case PinEvent::GroupReorder:
         {
-            int inx = pinGroupIndex(m,pgroup);
+            int inx = ActionPingroup::pinGroupIndex(m,pgroup);
             removeItem(ptiGroup);
             insertItem(ptiGroup, mRootItem, inx);
             break;
@@ -521,7 +523,7 @@ namespace hal
             QString netName;
             if (pin->get_net())
                 netName = QString::fromStdString(pin->get_net()->get_name());
-            ptiPin = new PortTreeItem(PortTreeItem::Pin,
+            ptiPin = new ModulePinsTreeItem(ModulePinsTreeItem::Pin,
                                       pin->get_id(),
                                    QString::fromStdString(pin->get_name()),
                                    pin->get_direction(),
@@ -554,7 +556,15 @@ namespace hal
             }
             removeItem(ptiPin);
             insertItem(ptiPin, ptiGroup, pinRow);
-            updateGroupIndex(ptiGroup);
+
+            // Unfortunately the event does not tell us where the pin was assigned previously. We have to update all group indices.
+            for (BaseTreeItem* bti : mRootItem->getChildren())
+            {
+                ModulePinsTreeItem* grpItem = static_cast<ModulePinsTreeItem*>(bti);
+                // check whether group still exists (might have been deleted when moving last pin)
+                if (mModule->get_pin_group_by_id(grpItem->id()))
+                    updateGroupIndex(static_cast<ModulePinsTreeItem*>(grpItem));
+            }
             break;
         }
         case PinEvent::PinRename:
@@ -591,12 +601,12 @@ namespace hal
 //        InputDialog ipd("Name of new group", "Name of new group:", onDroppedGroup->getData(sNameColumn).toString());
 //        if(ipd.exec() == QDialog::Rejected) return false;
         QList<u32> pins;
-        auto srcgroup = mModule->get_pin_group_by_id(static_cast<PortTreeItem*>(droppedGroup)->id());
+        auto srcgroup = mModule->get_pin_group_by_id(static_cast<ModulePinsTreeItem*>(droppedGroup)->id());
         for(const auto &pin : srcgroup->get_pins())
             pins.append(pin->get_id());
         if (pins.isEmpty()) return;  // no pins to move
 
-        auto tgtgroup = mModule->get_pin_group_by_id(static_cast<PortTreeItem*>(onDroppedGroup)->id());
+        auto tgtgroup = mModule->get_pin_group_by_id(static_cast<ModulePinsTreeItem*>(onDroppedGroup)->id());
 
         ActionPingroup* act = ActionPingroup::addPinsToExistingGroup(mModule,tgtgroup->get_id(),pins,row);
         if (act) act->exec();
@@ -605,7 +615,7 @@ namespace hal
         // with many ActionAddItemsToObject that contain a single pin each -> set destroys order of pins in source pingroup
     }
 
-    void ModulePinsTreeModel::dndGroupBetweenGroup(PortTreeItem *droppedGroup, int row)
+    void ModulePinsTreeModel::dndGroupBetweenGroup(ModulePinsTreeItem *droppedGroup, int row)
     {
         int ownRow = droppedGroup->getOwnRow();
         bool bottomEdge = row == mRootItem->getChildCount();
@@ -616,14 +626,14 @@ namespace hal
         act->exec();
     }
 
-    void ModulePinsTreeModel::dndPinOnGroup(PortTreeItem *droppedPin, BaseTreeItem *onDroppedGroup)
+    void ModulePinsTreeModel::dndPinOnGroup(ModulePinsTreeItem *droppedPin, BaseTreeItem *onDroppedGroup)
     {
-        ActionPingroup* act = new ActionPingroup(PinActionType::PinAsignToGroup,droppedPin->id(),"",static_cast<PortTreeItem*>(onDroppedGroup)->id());
+        ActionPingroup* act = new ActionPingroup(PinActionType::PinAsignToGroup,droppedPin->id(),"",static_cast<ModulePinsTreeItem*>(onDroppedGroup)->id());
         act->setObject(UserActionObject(mModule->get_id(),UserActionObjectType::Module));
         act->exec();
     }
 
-    void ModulePinsTreeModel::dndPinBetweenPin(PortTreeItem *droppedPin, BaseTreeItem *onDroppedParent, int row)
+    void ModulePinsTreeModel::dndPinBetweenPin(ModulePinsTreeItem *droppedPin, BaseTreeItem *onDroppedParent, int row)
     {
         int desiredIdx = row;
         ActionPingroup* act = nullptr;
@@ -637,14 +647,14 @@ namespace hal
         }
         else
         {
-            act = ActionPingroup::addPinToExistingGroup(mModule,static_cast<PortTreeItem*>(onDroppedParent)->id(),droppedPin->id(),desiredIdx);
+            act = ActionPingroup::addPinToExistingGroup(mModule,static_cast<ModulePinsTreeItem*>(onDroppedParent)->id(),droppedPin->id(),desiredIdx);
             if (!act) return;
         }
         act->setObject(UserActionObject(mModule->get_id(),UserActionObjectType::Module));
         act->exec();
     }
 
-    void ModulePinsTreeModel::dndPinBetweenGroup(PortTreeItem *droppedPin, int row)
+    void ModulePinsTreeModel::dndPinBetweenGroup(ModulePinsTreeItem *droppedPin, int row)
     {
         // row is needed for when groups can change its order within the module
         Q_UNUSED(row)
@@ -652,20 +662,20 @@ namespace hal
         auto pinToMove = mModule->get_pin_by_id(droppedPin->id());
         if (!pinToMove) return;
 
-        QString groupName = generateGroupName(mModule,pinToMove);
+        QString groupName = ActionPingroup::generateGroupName(mModule,pinToMove);
 
         ActionPingroup* act = ActionPingroup::addPinToNewGroup(mModule, groupName, droppedPin->id(),row);
         act->exec();
     }
 
-    void ModulePinsTreeModel::updateGroupIndex(PortTreeItem* groupItem)
+    void ModulePinsTreeModel::updateGroupIndex(ModulePinsTreeItem* groupItem)
     {
         PinGroup<ModulePin>* pg = mModule->get_pin_group_by_id(groupItem->id());
         Q_ASSERT(pg);
         for (ModulePin* pin : pg->get_pins())
         {
             int inx = pg->get_index(pin).get();
-            PortTreeItem* pinItem = mIdToPinItem.value(pin->get_id());
+            ModulePinsTreeItem* pinItem = mIdToPinItem.value(pin->get_id());
             Q_ASSERT(pinItem);
             pinItem->setIndex(inx);
         }
@@ -675,25 +685,25 @@ namespace hal
         Q_EMIT dataChanged(i0,i1);
     }
 
-    void ModulePinsTreeModel::insertItem(PortTreeItem* item, BaseTreeItem* parent, int index)
+    void ModulePinsTreeModel::insertItem(ModulePinsTreeItem* item, BaseTreeItem* parent, int index)
     {
         // fun fact: if an item is inserted above an item that is expanded, the tree collapses all indeces
         beginInsertRows(getIndexFromItem(parent), index, index);
         parent->insertChild(index, item);
         endInsertRows();
         //mNameToTreeItem.insert(item->getData(sNameColumn).toString(), item);
-        item->itemType() == PortTreeItem::Pin ? mIdToPinItem.insert(item->id(), item) : mIdToGroupItem.insert(item->id(), item);
+        item->itemType() == ModulePinsTreeItem::Pin ? mIdToPinItem.insert(item->id(), item) : mIdToGroupItem.insert(item->id(), item);
         //mIdToPinItem.insert(getIdOfItem(item), item);
     }
 
-    void ModulePinsTreeModel::removeItem(PortTreeItem* item)
+    void ModulePinsTreeModel::removeItem(ModulePinsTreeItem* item)
     {
         beginRemoveRows(parent(getIndexFromItem(item)), item->getOwnRow(), item->getOwnRow());
         item->getParent()->removeChild(item);
         endRemoveRows();
         //mNameToTreeItem.remove(item->getData(sNameColumn).toString());
         //for now, only ids of pin-items (since these functions are only relevant for dnd)
-        item->itemType() == PortTreeItem::Pin ? mIdToPinItem.remove(item->id()) : mIdToGroupItem.remove(item->id());
+        item->itemType() == ModulePinsTreeItem::Pin ? mIdToPinItem.remove(item->id()) : mIdToGroupItem.remove(item->id());
         //mIdToPinItem.remove(getIdOfItem(item));
         //delete item;
     }
diff --git a/plugins/gui/src/user_action/action_pingroup.cpp b/plugins/gui/src/user_action/action_pingroup.cpp
index c7950f69102e..d63b29ff9e2e 100644
--- a/plugins/gui/src/user_action/action_pingroup.cpp
+++ b/plugins/gui/src/user_action/action_pingroup.cpp
@@ -7,7 +7,7 @@
 
 namespace hal
 {
-    int pinGroupIndex(const Module* mod, const PinGroup<ModulePin>* pgrp)
+    int ActionPingroup::pinGroupIndex(const Module* mod, const PinGroup<ModulePin>* pgrp)
     {
         if (!mod || !pgrp) return -1;
         int inx = 0;
@@ -29,14 +29,14 @@ namespace hal
                       << " <" << pg->get_name() << ">\n";
             for (ModulePin* pin : pg->get_pins())
                 std::cerr << "     pin: " << pin->get_id() << " inx:" << pin->get_group().second << " row:"
-                          << pinIndex2Row(pin,pin->get_group().second) << " <" << pin->get_name() << ">\n";
+                          << ActionPingroup::pinIndex2Row(pin,pin->get_group().second) << " <" << pin->get_name() << ">\n";
         }
         std::cerr << "-------------" << std::endl;
         for (Module* sm : m->get_submodules())
             dumpPingroups(sm);
     }
 
-    int pinIndex2Row(const ModulePin* pin, int index)
+    int ActionPingroup::pinIndex2Row(const ModulePin* pin, int index)
     {
         auto pg = pin->get_group();
         if (pg.first->is_ascending())
@@ -44,7 +44,7 @@ namespace hal
         return pg.first->get_start_index() - index;
     }
 
-    int pinRow2Index(const ModulePin* pin, int row)
+    int ActionPingroup::pinRow2Index(const ModulePin* pin, int row)
     {
         auto pg = pin->get_group();
         if (pg.first->is_ascending())
@@ -57,7 +57,7 @@ namespace hal
         return (uint) pev;
     }
 
-    QString generateGroupName(const Module* mod, const ModulePin* pin)
+    QString ActionPingroup::generateGroupName(const Module* mod, const ModulePin* pin)
     {
         QString baseName = QString::fromStdString(pin->get_name());
         QSet<QString> existingGroups;
@@ -184,22 +184,6 @@ namespace hal
         return mParentModule->get_pin_group_by_id(grpId);
     }
 
-    void ActionPingroup::addUndoAction(PinActionType::Type tp, int id, const QString& name, int value)
-    {
-        ActionPingroup* undo = nullptr;
-        if (mUndoAction)
-        {
-            undo = static_cast<ActionPingroup*>(mUndoAction);
-            undo->mPinActions.append(AtomicAction(tp,id,name,value));
-        }
-        else
-        {
-            undo = new ActionPingroup(tp,id,name,value);
-            undo->setObject(object());
-        }
-        mUndoAction = undo;
-    }
-
 
     void ActionPingroup::prepareUndoAction()
     {
@@ -238,32 +222,23 @@ namespace hal
             if (gr.mDirection != PinDirection::none)
                 restoreActions.append(AtomicAction(PinActionType::GroupDirChange,gr.mId,"",(int)gr.mDirection));
         }
-        if (!restoreActions.isEmpty())
+
+        for (auto it = mTempUndoActions.rbegin(); it != mTempUndoActions.rend(); ++it)
         {
-            if (mUndoAction)
-            {
-                ActionPingroup* act = static_cast<ActionPingroup*>(mUndoAction);
-                restoreActions += act->mPinActions;
-                act->mPinActions = restoreActions;
-            }
-            else
-            {
-                mUndoAction = new ActionPingroup(restoreActions);
-            }
+            for (const AtomicAction& aa : (*it))
+                restoreActions.append(aa);
         }
 
         for (u32 grpId : mGroupToRemove)
         {
-            if (mUndoAction)
-            {
-                ActionPingroup* act = static_cast<ActionPingroup*>(mUndoAction);
-                act->mPinActions.append(AtomicAction(PinActionType::GroupDelete,grpId));
-            }
-            else
-                mUndoAction = new ActionPingroup(PinActionType::GroupDelete,grpId);
+            restoreActions.append(AtomicAction(PinActionType::GroupDelete,grpId));
         }
 
-        if (mUndoAction) mUndoAction->setObject(object());
+        if (!restoreActions.isEmpty())
+        {
+            mUndoAction = new ActionPingroup(restoreActions);
+            mUndoAction->setObject(object());
+        }
     }
 
     int ActionPingroup::pinGroupRow(const Module *m, PinGroup<ModulePin>* pgroup)
@@ -283,6 +258,7 @@ namespace hal
         mGroupRestore.clear();
         mPinsMoved.clear();
         mGroupToRemove.clear();
+        mTempUndoActions.clear();
         if (mObject.type() != UserActionObjectType::Module)
             return false;
 
@@ -304,7 +280,14 @@ namespace hal
                 if (it == mPinGroups.end())
                 {
                     pgroup = mParentModule->get_pin_group_by_id(aa.mId);
-                    if (!pgroup) return false;
+                    if (!pgroup)
+                    {
+                        // special case : the group delete command cannot be executed since the
+                        //                group was already deleted when re-assigning its last pin
+                        if (aa.mType == PinActionType::GroupDelete)
+                            continue;
+                        return false;
+                    }
                     mPinGroups.insert(aa.mId,pgroup);
                 }
                 else
@@ -320,13 +303,8 @@ namespace hal
             {
             case PinActionType::GroupCreate:
             {
-                int startIndex = aa.mValue;
-                bool ascending = true;
-                if (aa.mValue < 0)
-                {
-                    ascending = false;
-                    startIndex = -aa.mValue-1;
-                }
+                int startIndex = aa.mValue >> 1;
+                bool ascending = (aa.mValue & 1) > 0;
                 if (aa.mId > 0)
                 {
                     if (auto res = mParentModule->create_pin_group(aa.mId, aa.mName.toStdString(), {}, PinDirection::none, PinType::none,ascending,startIndex); res.is_ok())
@@ -350,46 +328,51 @@ namespace hal
             }
             case PinActionType::GroupDelete:
             {
-                int v = pgroup->get_start_index();
-                if (!pgroup->is_ascending()) v = -v-1;
+                int v = (pgroup->get_lowest_index() << 1) | (pgroup->is_ascending() ? 1 : 0);
                 u32 id = pgroup->get_id();
                 int ptype = (int) pgroup->get_type();
                 int pdir  = (int) pgroup->get_direction();
                 QString name = QString::fromStdString(pgroup->get_name());
                 if (!mParentModule->delete_pin_group(pgroup))
                     return false;
-                addUndoAction(PinActionType::GroupCreate,id,name,v);
-                addUndoAction(PinActionType::GroupTypeChange,id,"",ptype);
-                addUndoAction(PinActionType::GroupDirChange,id,"",pdir);
+                mTempUndoActions.append(QList<AtomicAction>({
+                    AtomicAction(PinActionType::GroupCreate,id,name,v),
+                    AtomicAction(PinActionType::GroupTypeChange,id,"",ptype),
+                    AtomicAction(PinActionType::GroupDirChange,id,"",pdir)}));
                 break;
             }
             case PinActionType::GroupMoveToRow:
             {
                 int inx = pinGroupRow(mParentModule,pgroup);
                 if (inx < 0) return false;
-                addUndoAction(PinActionType::GroupMoveToRow,pgroup->get_id(),"",inx);
+                mTempUndoActions.append(QList<AtomicAction>({
+                    AtomicAction(PinActionType::GroupMoveToRow,pgroup->get_id(),"",inx)}));
                 if (!mParentModule->move_pin_group(pgroup,aa.mValue))
                     return false;
                 break;
             }
             case PinActionType::GroupRename:
-                addUndoAction(PinActionType::GroupRename,pgroup->get_id(),QString::fromStdString(pgroup->get_name()));
+                mTempUndoActions.append(QList<AtomicAction>({
+                    AtomicAction(PinActionType::GroupRename,pgroup->get_id(),QString::fromStdString(pgroup->get_name()))}));
                 if (!mParentModule->set_pin_group_name(pgroup,aa.mName.toStdString()))
                     return false;
                 break;
             case PinActionType::GroupTypeChange:
-                addUndoAction(PinActionType::GroupTypeChange,pgroup->get_id(),"",(int)pgroup->get_type());
+                mTempUndoActions.append(QList<AtomicAction>({
+                    AtomicAction(PinActionType::GroupTypeChange,pgroup->get_id(),"",(int)pgroup->get_type())}));
                 if (!mParentModule->set_pin_group_type(pgroup, (PinType) aa.mValue))
                     return false;
                 break;
             case PinActionType::GroupDirChange:
-                addUndoAction(PinActionType::GroupDirChange,pgroup->get_id(),"",(int)pgroup->get_direction());
+                mTempUndoActions.append(QList<AtomicAction>({
+                    AtomicAction(PinActionType::GroupDirChange,pgroup->get_id(),"",(int)pgroup->get_direction())}));
                 if (!mParentModule->set_pin_group_direction(pgroup, (PinDirection) aa.mValue))
                     return false;
                 break;
             case PinActionType::PinAsignToGroup:
-                addUndoAction(PinActionType::PinAsignToGroup,aa.mId,"",pin->get_group().first->get_id());
-                addUndoAction(PinActionType::PinMoveToRow,aa.mId,"",pinIndex2Row(pin,pin->get_group().second));
+                mTempUndoActions.append(QList<AtomicAction>({
+                    AtomicAction(PinActionType::PinAsignToGroup,aa.mId,"",pin->get_group().first->get_id()),
+                    AtomicAction(PinActionType::PinMoveToRow,aa.mId,"",ActionPingroup::pinIndex2Row(pin,pin->get_group().second))}));
                 mPinsMoved.insert(aa.mId);
                 pgroup = getGroup(aa.mValue);
                 if (!pgroup) return false;
@@ -401,20 +384,23 @@ namespace hal
                 // dumpPingroups();
                 break;
             case PinActionType::PinRename:
-                addUndoAction(PinActionType::PinRename,aa.mId, QString::fromStdString(pin->get_name()));
+                mTempUndoActions.append(QList<AtomicAction>({
+                    AtomicAction(PinActionType::PinRename,aa.mId, QString::fromStdString(pin->get_name()))}));
                 if (!mParentModule->set_pin_name(pin, aa.mName.toStdString()))
                     return false;
                 break;
             case PinActionType::PinTypeChange:
-                addUndoAction(PinActionType::PinTypeChange,aa.mId,"",(int)pin->get_type());
+                mTempUndoActions.append(QList<AtomicAction>({
+                    AtomicAction(PinActionType::PinTypeChange,aa.mId,"",(int)pin->get_type())}));
                 if (!mParentModule->set_pin_type(pin, (PinType) aa.mValue))
                     return false;
                 break;
             case PinActionType::PinMoveToRow:
                 if (!mPinsMoved.contains(aa.mId))
-                    addUndoAction(PinActionType::PinMoveToRow,aa.mId,"",pinIndex2Row(pin,pin->get_group().second));
+                    mTempUndoActions.append(QList<AtomicAction>({
+                        AtomicAction(PinActionType::PinMoveToRow,aa.mId,"",ActionPingroup::pinIndex2Row(pin,pin->get_group().second))}));
                 pgroup = pin->get_group().first;
-                if (!mParentModule->move_pin_within_group(pgroup,pin,pinRow2Index(pin,aa.mValue)))
+                if (!mParentModule->move_pin_within_group(pgroup,pin,ActionPingroup::pinRow2Index(pin,aa.mValue)))
                 {
                     qDebug() << "move_pin_within_group failed";
                     return false;
@@ -498,7 +484,11 @@ namespace hal
         bool doNotDelete = false; // if there is a pin with the same name as the
         int vid = -1;
 
-        for (ModulePin* pin : groupToDelete->get_pins())
+        std::vector<ModulePin*> orderedPins = groupToDelete->get_pins();
+        if (groupToDelete->is_descending())
+            std::reverse(orderedPins.begin(), orderedPins.end());
+
+        for (ModulePin* pin : orderedPins)
         {
             if (pin->get_name() == groupToDelete->get_name())
                 doNotDelete = true;
@@ -571,13 +561,14 @@ namespace hal
         PinGroup<ModulePin>* pinGroup = m->get_pin_group_by_id(grpId);
         if (!pinGroup) return nullptr;
         bool toAscending = ! pinGroup->is_ascending();
+        int val = (pinGroup->get_lowest_index() << 1) | (toAscending ? 1 : 0);
         std::vector<ModulePin*> pins = pinGroup->get_pins();
         QString tempName = QUuid::createUuid().toString();
         QString grpName = QString::fromStdString(pinGroup->get_name());
         int grpRow = pinGroupRow(m, pinGroup);
         static int vid = -9;
 
-        ActionPingroup* retval = new ActionPingroup(PinActionType::GroupCreate,vid,tempName,toAscending ? 0 : -1);
+        ActionPingroup* retval = new ActionPingroup(PinActionType::GroupCreate,vid,tempName,val);
         if (toAscending)
         {
             for (auto it = pins.rbegin(); it != pins.rend(); ++it)
@@ -615,10 +606,8 @@ namespace hal
         : mId(pgroup->get_id()),
           mName(QString::fromStdString(pgroup->get_name())),
           mRow(pinGroupRow(m,pgroup)),
-          mStartIndex(pgroup->get_start_index()),
+          mStartIndex( (pgroup->get_lowest_index() << 1) | (pgroup->is_ascending() ? 1 : 0)),
           mDirection(pgroup->get_direction()),
           mType(pgroup->get_type())
-    {
-        if (!pgroup->is_ascending()) mStartIndex = -mStartIndex-1;
-    }
+    {;}
 }