Debug screen and F3 key combinations work in main menu (Java 1.21.9)

When pressing F3 or certain F3 key combinations in the main menu, the debug screen and related functions still trigger. This happens despite not being inside a game world.

Steps to Reproduce:

1. Launch Minecraft Java Edition 1.21.9.

2. Stay on the main menu (do not join a world or server).

3. Press F3 or combinations such as F3+1, F3+2, F3+F6, or F3+T.

Observed Result:

• The debug screen appears in the main menu.

• F3 key combos (reload chunks, reload resource packs, etc.) also activate, despite no world being loaded.

Expected Result:

• The debug screen and F3 functions should only work while in a game world.

• Nothing should happen when pressing F3 in the main menu.

Notes:

• This may be unintended behavior since the debug menu is designed for in-game diagnostics.

• Issue consistently reproducible.

• Tested on multiple computers with different hardware, issue occurs consistently.