Godot Editor stutters randomly due to the editor theme being unnecessarily regenerated

[Yni-Viar]

Tested versions

• Reproducible in 4.3 after 714effd
• Not reproducible in 4.3 before 714effd , 4.2.2

System information

Godot v4.3.stable - Windows 10.0.19045 - Vulkan (Forward+) - dedicated NVIDIA GeForce GTX 1050 Ti (NVIDIA; 32.0.15.6081) - Intel(R) Core(TM) i5-10400F CPU @ 2.90GHz (12 Threads)

Issue description

I got upgraded my projects to Godot 4.3 from 4.2.2 and noticed, that it stutters randomly (I tested 4.3 Dev 6 and 4.2.2 stable - no issues) if V-Sync is enabled.
Godot 4.3 Beta 2, RC 2 and 3 partially trigger this bug.
Below I posted --verbose log, what Godot did when it was stuttering

EditorTheme: Generating new theme for the config '66886095'.
EditorTheme: Can keep old icons, copying.
EditorTheme: Generating new fonts.
EditorTheme: Generating new styles.

Steps to reproduce

For 4.3.stable: Create empty project -> open the editor -> see stutter randomly
For 4.3 Beta 1, Beta 2, RC 2 and 3: Create empty project -> open the editor -> set V-Sync to enabled/adaptive in editor settings -> zoom in and out repeatedly (when window is inactive) -> see stutter randomly

Minimal reproduction project (MRP)

Mostly unneeded, occurs even in empty project.
Here I leave the example one, created in 4.3.stable
test.zip

[Yni-Viar]

Edit: in large projects editor stutters even if V-Sync disabled.

[Yni-Viar]

The bug likely was introduced between 4.3 dev 6 and beta 1.

[Yni-Viar]

I investigated into the problem, and found, that #89033 is the source of bug. (I debugged stable version) Also I checked build before commit (no issues) and after commit (the bug is triggered).


(screenshots from 4.3.stable)