Doing so reduces the number of alternate Action Bars that are available via the up and down arrows situated to the right of the primary action bar. The advanced interface options allow a player to add up to five other action bars (bottom left, bottom right 1, bottom right 2, right 1, and right 2) to the screen. Buttons which used downranked versions of spells and abilities and buttons on your inactive spec's skill bars will not be updated.
When you learn a new rank of an ability or spell, all buttons on your currently active spec's action bars which previously used the highest available rank will be updated to use the new highest rank. To the right of the command shortcuts are gold up ( ↑) and down ( ↓) arrows to switch to alternate Action Bars (see below).Once placed, they can be activated with a quick hotkey or mouse click. Holds any spells or abilities you place here from your Spellbook and Abilities window.
