When I press a letter key alone, it will have the effect of pressing it with a modifier key

- [x] I have read the [FAQ](https://github.com/Genymobile/scrcpy/blob/master/FAQ.md).
- [x] I have searched in existing [issues](https://github.com/Genymobile/scrcpy/issues).

**Environment**
OS: macOS 12.6.6
scrcpy version: 2.0
installation method: brew
device model: samsung z fold4
Android version: 13

**Describe the bug**

Sometimes, when I press a letter key alone, it will have the effect of pressing it with a modifier key. For example, when I only press `F`, it will make the window full screen (like pressing `CMD+F`). It can be temporarily solved by switching the focus of the window, and there is no certain way to reproduce this problem.

Do you have any ideas for debugging (for example, what kind of software may conflict with it, or provide a version that can print more detailed logs)?

Start by reproducing the keyboard-focus issue on macOS 12.6.6 with scrcpy 2.0, a Samsung Z Fold4, and Android 13, then collect more detailed logs as suggested in the issue. Done means identifying the modifier-state or focus interaction and confirming that pressing a letter alone no longer triggers the corresponding modified shortcut.

Written by the indexing model from the issue text.