Set 3D cursor button randomly set to LMB in Edit Mode Blender 2.8 randomly sets the LMB to set the 3D cursor in Edit Mode despite the keymap settings stating that is it LMB. The LMB is selecting in Object Mode but not in Edit Mode.

It does this in only one project. Other projects still use the LMB for selecting in Edit Mode.

I've tried to reset the factory setting via File -> Default -> Load Factory Settings. I've tried Preferences -> Load Factory Preferences. I've restarted Blender. Like it was suggested in this question.

But nothing works. It's like I accidentally pressed a button combination to set it like this. Does anybody know what I can do the make selecting in Edit Mode the LMB again?
Press the cursor icon in the left toolbar (you can call it by pressing T)
(as pointed out by @FFelller)