TD, LR and links are all ignored and graph is completely restructured by adding an arrow

[Grunthos]

Description

The title covers the problem, the examples below illustrate it:

Steps to reproduce

Simple layers:

flowchart TB

    %% Top layer
    subgraph Top[The World]
        direction LR
        Top1 ~~~ Top2 ~~~ Top3
        Top1
        Top2
        Top3
    end

    %% Second layer
    subgraph Middle
        direction LR
        Mid1
        Mid2
        Mid1  ~~~ Mid2
    end

    %% Third layer
    subgraph Bottom
        direction LR
        Bot1
    end

    Top ~~~ Middle ~~~ Bottom

flowchart TB

    %% Top layer
    subgraph Top[The World]
        direction LR
        Top1 ~~~ Top2 ~~~ Top3
        Top1
        Top2
        Top3
    end

    %% Second layer
    subgraph Middle
        direction LR
        Mid1
        Mid2
        Mid1  ~~~ Mid2
    end

    %% Third layer
    subgraph Bottom
        direction LR
        Bot1
    end

    Top ~~~ Middle ~~~ Bottom

Loading

Now just add a single arrow (last line):

flowchart TB

    %% Top layer
    subgraph Top[The World]
        direction LR
        Top1 ~~~ Top2 ~~~ Top3
        Top1
        Top2
        Top3
    end

    %% Second layer
    subgraph Middle
        direction LR
        Mid1
        Mid2
        Mid1  ~~~ Mid2
    end

    %% Third layer
    subgraph Bottom
        direction LR
        Bot1
    end

    Top ~~~ Middle ~~~ Bottom
    Top1 --> Mid1

flowchart TB

    %% Top layer
    subgraph Top[The World]
        direction LR
        Top1 ~~~ Top2 ~~~ Top3
        Top1
        Top2
        Top3
    end

    %% Second layer
    subgraph Middle
        direction LR
        Mid1
        Mid2
        Mid1  ~~~ Mid2
    end

    %% Third layer
    subgraph Bottom
        direction LR
        Bot1
    end

    Top ~~~ Middle ~~~ Bottom
    Top1 --> Mid1

Loading

And the whole this becomes chaotic.

Screenshots

No response

Code Sample

See above.

Setup

• Mermaid version: 9 to 11.4
• Browser and Version: [Firefox]

Suggested Solutions

Allow some way to create arrows that do not change structure.

Additional Context

This seems to be a very long-term issue.

[Grunthos]

I am aware of this closed issue #815 which seems to relate to similar problems.