Can't erase dimensions

I was working on a legacy SW (I use SW 2007) model anddrawing that I didn't originally create. Initially, the filesworked fine. But now, if I try to modify the drawing such as removea dimension, it won't delete. When I select a dimension and thenthe Delete command, the flyout appears but it will not delete.

Anyone know what the solution?

Thanks in advanceSolidworksGeneral