Well, this was a new one. Suddenly the magic bar http://i.imgur.com/ZmNK8sP.jpg. I haven't changed anything that could affect it that I know, so It's quite weird. I'm using Sky UI, Immersive HUD and Less Intrusive HUD. Anyone who has an idea what might have caused it and how to fix it? Perhaps reinstalling the HUD mods will help, but it would be nice to know what happened as well.

Maybe it has something to do with your FOV. Try setting it to 85 and see how if that changes anything.

Less Intrusive HUD is the obvious culprit. Straighten up the magicka bar in the settings.

No, that doesn't help - and it shouldn't be the cause as I've been playing with FOV 90 for months w/o issues.

Thanks, that was it - and know I know how it happened as well. I installed http://skyrim.nexusmods.com/mods/32676/? and when trying to place a chest I activated Less Intrusive HUD's edit mode and assumed it was the chest mod's. No wonder it didn't work on the chest...