Up until now, I had assumed that a broken chest (one that was stuck open) was broken for good until a server reset. You where never going to get anything out of it once it got stuck open due to lag, or the "loot all" button.
But no, it's not hopeless!! There is a trick you can do to get chests that are stuck open to close. I saw it done yesterday, and today tried it myself on a broken chest and it worked! The chest closed!



Here is how you do it. First, enter search mode. Then click on the chest to open it, and as soon as the chest opens use the WASD keys to step away from the chest. The timing has to be perfect, so it might take 10 or 15 tries to get it just right. But if you step back from the chest immediatly as you try to open it, it should re-close itself.
If that wasn't clear, let me know and I'll try to explain it better. I would never have believed this myself if I didn't see it in action. Try it! Our chest breaking epidemic might just be at an end!