VST window losing focus but not moving to background

[Monospace-V]

Bug Summary

Clicking any other window when a VST GUI is open makes the VST window transparent but doesn't shift it entirely to background. Video under screenshot should explain the problem.

Steps to reproduce

1. Load any VST
2. Show VST GUI
3. Try moving VST GUI to background by clicking any other in-LMMS window

Expected behavior

VST GUI moves to background

Actual behavior

Varies with the window being clicked to focus on. Either GUI remains in focus while titlebar of VST window goes out, or entire GUI remains in focus as titlebar becomes transparent.

Screenshot

Untitled_.-.LMMS.1.3.0-alpha.1.33+g4f74151f0.2021-07-26.21-16-04.mp4

Affected LMMS versions

This specific version of 1.3 alpha on Windows:

[DomClark]

What embedding mode are you using? I get a similar effect using "Embed using Qt API" - try using "Embed using native Win32 API" instead.

[Monospace-V]

I was using QtAPI. Win32 API does not cause the issue.

[Rossmaxx]

Looks like this is fixed on master now automatically (or this might be a qt version thingy). But I get something else.

lmms-qembed-demo-resize.mp4

I tried a fix in this branch but doesn't seem to work. Will open a PR once I get it working.

@DomClark You got any ideas?

[Rossmaxx]

Tried googling for a fix but all I understand is that this is a Qt issue from https://bugreports.qt.io/plugins/servlet/mobile#issue/QTBUG-39362