logout and open a console using Ctrl+Alt+F1 and login as yourself.
mv ~/.config/xfce4 ~/.config/xfce4.bak
Ctrl+Alt+F7 and log back in.
Warning: This will 'reset' your Desktop 'Experience' to 'default' settings
This does not affect your "apps" other than where their placement on the desktop and/or panels.
if that doesn't work, just mv the entire ~/.config to ~/.config.bak and log back in.
Worse case scenario, mv those/it back.