When clicking on a modded GUI button besides this one (when this mod's one is closed), the game CTD's due to control.lua:29 (specifically at "b.gui.left["sc-main"].sc.c"). This is likely due to "sc-main" not existing (it's null). I presume this is because when the character toggle menu is closed, it destroys it. This should be an easy fix of first checking that sc-main exists before trying to reference its values

Update: I modified it so before checking for "sc-main", it checks that it's not null (or nil in lua) first in the if statement. If it is nil, short-circuit evaluation prevents the rest of the if from being evaluated (as the first part being false with an and following makes it impossible for the whole if to be true regardless of the rest of the partial expressions)
So the whole line ends up at (elseif b.gui.left["sc-main"] ~= nil and event.element.parent==b.gui.left["sc-main"].sc.c and b.driving==false then)

(accidentally hit quote and made this message)

(oops did it again)