Ah, I see - none of those buttons have valid controller events. Thus, the game has no way to look up events associated with those buttons. IconButton is intended to have a mapping both for keyboard and for controller. If you just want to make a mouse & keyboard button with no controller equivalent, there's no need to use IconButton at all, since most of its conveniences are tied to picking the right icon set and allowing for remapping, none of which is offered for keyboard shortcuts. You can just make your own imagebutton with a keysym.