Toolbar is locked after the 21.1.49 update

From your screenshot I can’t tell any unexpected behaviour. The formatting buttons are grayed out if no field is focused.

From which version did you update? Since 2.1.49 didn’t bring any new features, I guess your previous version was below 2.1.45 (when the new toolbar as introduced)?

You need to uninstall Frozen Fields. The functionality of Frozen Fields is now built-in, and the add-on causes this bug.