That is the gist of it; basically I can no longer click (LMB or RMB) on a tab to access a window, nor can I click on an item on the right of the xfce panel. The only way to change windows is by ALT+TAB or by pressing SUPER (configured to open whisker menu).
Steps to reproduce:
I believe what I did was: press ALT+F11 and then repeat to undo full-screen mode.
I have not been able to find anything about this in the bugtracker, so maybe this is a feature, but I wasn't able to find any settings regarding the issue.