when a paladin hits level 42, the class bar changes from 2 buttons to 3. if dominos is active at that time, the button creation fails. After logging off, wow will crash on log in while trying to create the new button.

The issue can be worked around by logging off, disabling dominos and logging back on once. then dominos can be re-enabled and the third button is there.

Please add the ability to change the number of buttons on the class bar (or automatically resize, or start at the max number)

This should be resolved in the 5.3 build