Draw Mask control point labels covering up control points...
I once had this issue years ago. And can't remember the solution. Other than constantly zooming in and out on the image ... which in this case is very tedious as there is a lot of masking to be done, and moving masks.
See attachment. The label covers up the point. The point can't be accessed.
MacBook Pro (15-inch Glossy), Mac OS X (10.6.8)