Camera becomes unrotatble. Restart not helping

After working a while in Blender, the camera doesn’t respond on rotates anymore.
Situation: in Object-mode, I select the camera, and use R to rotate. The camera does not rotate at all, while the status-bar says ‘Rot <angle>’.
Then I complete my rotation (left-click), and still nothing happens.
I tried rotating on 1 axis only (R, x/y/z) but nothing.

The only thing I cán do then, is moving the camera.

Q: Is this a bug or a ‘feature’ I turned on? (Restart doesn’t work, might be in the .blend)

On the header, just to the left of the layer buttons is an icon with 3 cubes on it with a tooltip that says “Move object centers only”. It’s restricting the rotation.


So it’s a feature I turned on, accidently. :Z

Thank you very much Fligh %! I really appreciate your help. Arigatou…