Pressing the Alt key in a UI causes the game to freeze

Description:

When pressing the "Alt" key in a UI, both the game screen and the UI freeze. They return to normal when clicking the mouse or pressing any key on the keyboard.

Steps to reproduce the issue:

1. Open Minecraft

2. Open a UI (like chatbox)

3. Press the “Alt” key

Expected result:

The game does not freeze, just like in any other historical version of Minecraft.

Actual result:

Your game will freeze in 1.21.120 until you click with the mouse to resume.