@yanta said in [Opera 66.0.3480.0] Cannot exit fullscreen mode: @netlord said in [Opera 66.0.3480.0] Cannot exit fullscreen mode: @sgunhouse Same here. Os is Debian Sid No key combination, no menu, nothing works. On Windows 10, in addition to the methods already mentioned, you can also leave the full screen mode by pressing the ESCAPE key. Does this work for you? (Opera 66.0.3480.0, installed in stand-alone/portable mode). It seems to work but this is the most awful, bad and horrific solution! I had two windows with a lot of tabs and all are gone now. Worst solution of all time! Additionally - I just updated to 66.0.3489.0 and the problem persists. sigh