Folks: There are a number of cosmetic but nonetheless distracting repaint/flicker issues while scrolling a diagram using the scrollbars: 1. There are two additional unnecessary repaints on mouse-up on scrollbar and one on the zoom slider. 2. Especially grating: there are additional intermediate repaints during scrolling, that appear to be ...

First, thanks to all on this thread for the attention to detail and iterative refinement -- really makes a difference. One additional observation:  When zooming using Ctl-mousewheel, MR paints the diagram at every intermediate zoom factor -- so if I zoom five clicks, it repaints five times, which is slow, and doesn't return ...