For a quick fix, try to just bind shift + = on your main toon to that same button on Bottom Left Bar and leave the action slot empty?

From what I remember if you don't have anything bound to shift/alt/ctrl 'x' when you press shift+'x' or ctrl+'x' it will just default to 'x' w/o the modifier. This could be pulling information out of my ass as I'm 6 beers into a 12 pack but give it a shot and let us know what you find.