I have the same problem when I use the zoom feature in 6.10 working on a PV600+ application. One time, the button turned gigantic and moved all the way to the left to the point where I could only see its rightmost "handles" but could not grab them. I could not select the object or move it. I had to select all (CTRL+A) and then move everything on the screen to the right, fix the ginormous button, then move everything else back into place.
To avoid the problem, I just quit zooming in. Now I just deal with staring at the tiny little indicators while I am editing.