Switch to Chrome. Now do one of the following:
- Move the mouse pointer to the upper right corner of the screen. When the menu bar slides down, click on the blue double arrow icon.
- Move the pointer to the top of the screen. When the menu bar slides down, click View > Exit Full Screen.
- Type Command-Control-F.
ahh! thank you so much! i knew it was something simple, but as i never use mission control i was having the hardest time finding the solution. i found out what i did. i was using spectacle to resize windows. Command-Option-F is the maximize window command for spectacle, i must have hit Control instead of Option.