Flash MX 2004.
toolObj.setToolTip(toolTip)
toolTip A string that specifies the tooltip to use for the tool.
Nothing.
Method; sets the tooltip that appears when the mouse is held over the tool icon. This method is used only when you create extensible tools.
The following example specifies that the tooltip for the tool should be PolyStar Tool. This code is taken from the sample PolyStar.jsfl file (see "Sample PolyStar tool"):
theTool = fl.tools.activeTool;
theTool.setToolTip("PolyStar Tool");