It would seem that there is a bug in the IMVU homepages causing the drops down menus for the edit controls to disappear when you try to use them. If you are experiencing this problem, there is an official thread on IMVU here:
http://www.imvu.com/catalog/modules.php ... p&t=481497I myself have experienced this problem and I've found that if you click it multiple times, eventually it will work. Others have suggested holding down the edit button and dragging it into the panel works while others have said to enable panel borders to fix the bug.
Hopefully IMVU fixes it soon, it makes working on this block script very irritating.