Just noticed this minor bug whilst looking up all the hotkeys. The F9 button still works though, but still, I couldn't find it on any of the drop-down menus.
Continuing with the subject, may I also suggest that there's a way to display whether the Grid toggle is turned on or off? I'm thinking somewhere at the corner of the screen similar to the co-ordinates of terrain pieces and objects.
Commit 0255ef3 adds a menu option (under Tools). Commit 546fc96 adds a visible indicator in the bottom right corner.