UI dropdown menus render behind the main application window after toggling Developer Tools

### Type
Bug

### Description
After opening the Developer Tools, inspecting elements, and maximizing the Developer Tools view, closing or switching back to the main VS Code window breaks the Z-index/window layering of top-bar dropdown menus. Menu items render behind the main editor window instead of in the foreground.

### Environment
* **VS Code Version:** 1.88+
* **OS:** Windows 10 / 11 (Git Bash terminal)
* **Extensions Disabled:** Yes (`code --disable-extensions`)

### Steps to Reproduce
1. Launch VS Code with extensions disabled (`code --disable-extensions`).
2. Open Developer Tools (`Help` > `Toggle Developer Tools` or press `F12`).
3. Maximize or expand the Developer Tools window to full screen.
4. Close the Developer Tools window (`F12` or click `X`).
5. Click on any menu item in the top menu bar (e.g., `File`, `Edit`, `Selection`, `View`).

### Expected Result
The dropdown menu opens directly below the clicked item, fully visible in the foreground on top of the main VS Code window.

### Actual Result
The dropdown menu renders behind the main application window, hiding the menu choices behind the editor interface.