I cannot supply screen shots of "a jerky movement when dragging ScrollList vertical scrollbars". when the mouse is used to drag the vertical scroll slider down, the slider first moves and is drawn correctly, then it "jumps" back up a distance (being redrawn), before finally being redrawn in the correct position again. I sounds similar to the "resize using top of FileSelector" described above..I don't have this. You could try a screenshot from the aranym-menu (I assume this is on aranym?)
Now I think I know what you mean: The up-move is blitted, while the down-move is redrawn and the scrollbar "jumps". Not really nice, but it works. I'll introduce the blitting later again.
That cannot be screenshot, I agree! -Helmut