If you plan on leveling a character in record time during the Remix: Mists of Pandaria event then this is a must have! Loot all of your items and threads without worrying about looting any of your bonus experience, so you can save that for later.
Inspired by Remix Mail Helper, I noticed a large amount of lag and inconsistency in looting items to where you would have to click the button multiple times just to get all of your items, all the while the "Open All" button works perfectly every time? What's up with that!? Well, the issue is completely fixed with my addon.