Thank you for your post.
This has been previously reported (not by someone on the forum), and our Development and Testing departments are aware of this issue. You will notice that any time you move the cursor while still on the object, the tooltip will re-evaluate.
I have attached your post to the original report. When more information becomes available, I will let you know.
And does this happen on windows systems?
An entry in the Known Bugs List has been linked to this Issue Report. Any Comments/Questions/Suggested Corrections should be posted here or in a new thread. Please do not post such comments to the Known Bugs List thread.
This occurs on both Mac OS X and Windows.