Shotcut crashes after I change the theme if a filter that uses VUI is applied to the current clip

Is this happening to anyone else? I don’t want to post about a bug that’s only happening to me again, but I can’t know that unless I make a post here.

Steps to reproduce:

  1. Lanuch Shotcut.
  2. Open a video file or image file.
  3. Apply a filter that uses VUI to the Source tab or a clip in the Timeline.
    I’ve tested Crop: Rectangle, Text: Simple, Text: Rich, and Position, Size & Rotate, and all of them are factors in the crash.
  4. Choose a theme different from the current one from Settings > Theme.
  5. Shotcut crashes.

After applying a filter, the parameters don’t have to be changed. The bug happens regardless.

The VUI has to be visible in the player for this crash to occur. If a filter that uses VUI is applied to a deselected clip on the Timeline, Shotcut doesn’t crash.

A. Tested on Windows 10
B. Tested on two PCs with different CPUs.
C. Tested on v21.05.18, but as far as I know, this bug has been happening for a long time. v19.01.27 exhibits this bug.

Same here on 21.05.18. After the restart of Shotcut it recovers the files (last loaded video with the VUI filter - SPR in my case), if you then change the theme, it works fine, Shotcut informs you that it requires a restart to apply the new theme changes.

Replicated

I reproduced it too, and the only fix I found so far is to not change the theme straight away but upon restart.

This is fixed for the next version 21.06