[trunk] R4778 navigator
The navigator can get into a state where it will continuously redraw the images (or not at all). The only way I can reproduce this is with a multi-page score (say about 5 or 6) and slowly change the navigator size until it is switching between having a scroll bar and no scroll bar.
If I resize the navigator a bit more then the images will redraw properly again, and there will be a scroll bar, a bit smaller and it will also redraw properly without a scroll bar. There is a small "window' where it can't redraw properly.