User is unable to move widgets on his dashboard

Hi,

I have two problems with one of my user's dashboard. The first one has to do with an empty widget that appears at his dashboard page. Although he is trying to delete it, the wigdet remains at the same page. The widget has no title or text and he also tried to remove it from the 'manage page' link.

The other problem is that the same user is not able to move his widgets. Drag 'n drop is not possible.

I don't know if the two problems are related but any help would be appreciated.

thank you