[BUG] TkinterOS system UI fails to enter fullscreen mode correctly on Windows 11.

[WindowsUninstaller]

System Info

• OS: Windows 11 23H2
• Screen Resolution: 1920 x 1080
• Display DPI: 125%
• Python Version: 3.14.0

Description

When enabling fullscreen mode for the TkinterOS system UI (which triggers fullscreen automatically on launch), the window does not cover the entire screen as expected. The Windows taskbar and other desktop elements (e.g., Visual Studio Code window) remain visible, and the TkinterOS window is restricted to only a portion of the screen. This issue is highly likely related to the 125% DPI scaling setting on Windows 11.

Reproduction Steps

1. Set the display resolution to 1920 x 1080 on Windows 11 23H2.
2. Adjust the display DPI scaling to 125%.
3. Launch the TkinterOS application (it enters fullscreen mode automatically on startup).
4. Observe that the window does not occupy the full screen area (issue reproduced successfully).

Screenshot