I had that same problem. I ended up having to change UI's . I had 2 addons that seems to screw up everytime I minimized or maximized bartender4 and btex skins. So I ditched my whole ui for nUI and I haven't had a problem since. The only time I didn't have a problem is if I resized the wow's in windowed mode by scaleing them with the mouse and not the minimize maximize options.