Direction tag isn't working if inner node doesn't have link

[soichisumi]

Description

Direction tag isn't working if inner node doesn't have link.
As workaround, we can use invisible link.

Problem

flowchart LR
A-->B
subgraph sub
direction TB
    C
    D
    F
end

flowchart LR
A-->B
subgraph sub
direction TB
    C
    D
    F
end

Loading

Workaround

flowchart LR
A-->B
subgraph sub
direction TB
    C~~~D~~~F
end

flowchart LR
A-->B
subgraph sub
direction TB
    C~~~D~~~F
end

Loading

Steps to reproduce

described as above

Screenshots

described as above

Code Sample

described as above

Setup

• Mermaid version: the version github is using. https://mermaid.live/ is also same.
• Browser and Version: [Chrome]

Suggested Solutions

No response

Additional Context

No response