When you use the guild-bank and drag-drop several items out of it, sometimes the item you moved last not shows up in your inventory. The slot is occupied by that item, but you cannot interact with it. The issue gets solved, once you move another item from the bank into your inventory. Then, the first one instantly becomes visible where you moved it and you can use it as intended.
Tis a minor bug, I got used to it over the past months. But it looks like one of those, ANet would fix within seconds, so I give it a try. Happy hollidays and keep up the good work with gw2.
dulfy-effect: Knowledge is power. But without fame, you are just a freak.