Esc > Keybindings > find what Shift + Numbers are bound to(You have like 8-9 hotkey bars available under your "main" hotkey bar, which, surprise,(not a sarcastic reply) are accessed by pressing shift + # to skip to a specific bar, or shift + arrow to scroll through them 1 by 1; I unbound mine before even multiboxing cuz I Kept hitting the damn thing in pvp and lost my spells at very bad times lol