Editor windows resize unevenly with visual glitches when dragging their borders using Direct3D 12

Steps to reproduce

1. Create a new project
2. Go to Edit > Project Settings > Player > Other Settings > Rendering
3. Disable Auto Graphics API for Windows and set the Graphics API to Direct3D 12
4. Drag the border of the Hierarchy or Inspector window to resize it
5. Observe the resizing behavior

Actual result: The window border does not move smoothly, and visible graphical glitches occur during resizing
Expected result: The window border moves smoothly without any visual glitches

Reproducible with: 6000.0.0f1, 6000.0.83f1, 6000.3.23f1, 6000.6.0f1, 6000.7.0a6

Reproducible on: Windows 11
Not reproducible on: No other environments tested