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 positioned incorrectly.  This is especially noticeable when zoom is set above 100%, say 125%.  While moving the scollbar to the left, the diagram contents are supposed to move to the right, but instead alternate between jumping left and right (and since it's now Friday at midnight.... "let's do the time warp again!" )

At zooms below 100% there's the same multi-step effect but never backwards, and at 100% there are repaints but overdrawn on one another.

3. Probably no need to say so, but most desirable is to manage to avoid complete visible repaint of the white background (off-screen bitmap blah blah blah), as the white flashing is the most distracting part of all.

All of this highlighted because the rendering of the tables with gradient and nice icons is otherwise so pretty!

-- Graham