Project Settings vertical separator position is not synchronized with the mouse position when dragging it horizontally

How to reproduce:
1. Create and open a new project
2. Open the “Project Settings“ in (Edit > Project Settings) in the Toolbar
3. Click and drag to the sides the vertical separator
4. Observe the Project Settings window while moving the separator

Expected result: The separator sticks to the position of the mouse
Actual result: The separator goes beyond the mouse position

Reproducible in: 6000.0.0b11, 6000.0.15f1
Not reproducible in: 2021.3.42f1, 2022.3.42f1, 2023.3.0b10

Reproduced on: Windows 11 Pro (23H2)
Not reproduced on: No other environment tested

Note: Other separators like in the Project tab or the horizontal separator in the Console are not affected