FlowcharWindow causes GUI Layout error in the Unity 2021 LTS (Severe BUG!)

[breadnone]

Describe the bug
GUI Layout error will be thrown, every time there is an action in the Flowchart graph in Unity 2021 LTS and will cause StackOverflow exception.

To Reproduce
Install Fungus in Unity 2021 LTS, create a flowchart, then Open Flowchart Window. The error will be shown

Additional context
It's a very sever bug, almost makes Fungus unusable in projects!

[oldbloodgames]

Just seconding the issue. This bug essentially makes using Fungus in Unity 2021 impossible with the perpetual crashing from the StackOverflow exception.

[DrXand]

Same problem on any version of Unity 2021, LTS or not. Because of this, I can't migrate my project to the new version of the engine.

[addie-lombardo]

Was about to finally leave an issue for this and glad to see others have been seeing it too and it's not just me. I did do a quick run through the script and all the Begin/End methods are being called properly (which is what the error warns you about) so I'm at a little bit of a loss as to what changed in the change from 2020 to 2021. I'll dive deeper on this because it needs to be fixed, I'm sick of Unity regularly crashing!

Edit: I narrowed it down to something is happening in the DrawOverlay method of FlowchartWindow which is causing the error to be thrown. I've tried commenting out chunks of it to find what exactly it was but it only fixed the error if I commented out the whole method.

[breadnone]

Found a fix for this, will make a pr soon

[stevehalliwell]

The linked pr seems straightforward enough. But can someone provide detailed repro steps for unity 2021.3.1 as I'm not able to create it other than as a one off when adding a variable to a flowchart via the in flowchartwindow add button. So we can go through the steps to check for other gremlins hiding in there.

[breadnone]

The linked pr seems straightforward enough. But can someone provide detailed repro steps for unity 2021.3.1 as I'm not able to create it other than as a one off when adding a variable to a flowchart via the in flowchartwindow add button. So we can go through the steps to check for other gremlins hiding in there.

@stevehalliwell Another way to trigger the error is by clicking the flowchart gameObject in the hierarchy then click the Open Flowchart Window. Basically anything that triggers the opening of a flowchart would trigger it.

Another thing that CAN'T trigger the error is when the domain-reloading is done then very quickly(like immediately) open the flowchart window, we can sometimes open the flowchart window without any hiccups/issues

Edit: You should test it in 2021 LTS and above, as they changed some of the old IMGui api in preparation for making the default ui-toolkit for the default Editor api as mentioned here #1051

Edit2 : Docking/Undocking the opened Flowchart window will trigger the error as well