Open and close the GUI with the same key bind. Would improve speed and easy of use greatly instead of having to reach for escape each time. For example I could bind to mouse 4 and my operation would be - press mouse 4 > open GUI > press left mouse on a button > press mouse 4 to close GUI. Not even moving my left hand from WASD. speed.
You want to take it a level further? Hold button for GUI. Hold > click a few buttons in GUI > release.
Either way I'd be happy. Thank you for considering!