leighos,

What exactly is the problem? Is there a cloud of nothingness that follows the cursor around when you try to place a dimension? Does everything stay hidden after the cursor is moved? Is the dimension covering the lines? Are you in a part file and you are editing a sketch or are you in a drawing file and are trying to add dims to a view? Try to describe the exact situation and I'll see if I can talk you through the problem.

David