Enter a module and hit the little button to go to your inventory. First, the screen isn't draggable, so you have to hit the other little button to even see your mule. But more importantly you can't click on your inventory slots. Neither to have it sort your mule for you or to unequip something. (This isn't a twinky bug. You totally need to do it when going to a low level dungeon to redo your talent weapons.)
