You used to be able to right click and choose "pause" during show and erase which would allow you to pull dimensions or annotations out of the way so you could pick the ones you wanted. According to PTC Case # 12538105:
"I have just received confirmation from Product Management that the new Show Model Annotations functionality does not have a Pause capability. It was not forgotten, it was removed."
This functionality also used to allow you to use the search tool to find a specific dimension if you knew the variable name (ie d123).
