It seems like the game doesn't restore its window focus correctly since a 1.19 snapshot.

When the game window loses focus and it's restored back, it becomes impossible to look around while holding any mouse button (left, middle or right). It can only be fixed by pausing and unpausing by pressing Escape.

I play on Linux and I'm not sure if it affects other platforms as well.

This issue was introduced in the 1.19 snapshot 22w16a. It doesn't exist in 22w15a and prior versions of Minecraft. Maybe it's due to the LWJGL update to 3.3.1, but it's just my wild guess.

Steps to Reproduce:

1. Enter a single-player world or join a server.
2. Lose window focus by Alt-Tabbing or through some other method.
3. Focus back on the game window.
4. Now it depends if the game paused after losing focus or not. It doesn't do it consistently for me. But when it doesn't pause (for me it's the case most of the time):
5. Hold any mouse button and try to look. You can't.