Cannot transform by draging handles

Hi, I've been looking for a solution all morning...

I cannot drag handles to reshape forms, at least with some objects I can and others I don't. E.g. I make a rectangular shape en just want to drag 1 corner to change the height or width. I can only move the object. It's not that I don't have handles (used Ctrl Shift B), I just can't drag them... When I use "e" to go to the transformation tool I can see the special transform signs, one moment I can transform but only from the top corners and on another object I can't do anything. When I have a group of objects I have no problems transforming them so up till now it only happens with simple rectangles.

I've already updated Illustrator to the latest version but without any success... Anybody ideas? I'm quite desperate for the moment... Thank you in advance