Just to say that I've just tried Wine 20050524 and all the problems are *almost* fixed (20050419 was still broken, so the fixes have crept in since then)
A new image in PSP correctly draws/clears itself.
Tooltips *almost* clean up after themselves, except when the tooltip's right edge goes over the drawing window's right edge, or the tooltip's bottom edge goes over the drawing window's bottom edge. In those two situations traces of the tooltip get left behind on the image canvas until the display is refreshed manually (desktop switch, dragging another window in front etc.). No problems at the top or left boundaries though, just right / bottom.
Pop-up menus behave in exactly the same way as tooltips; they get cleared OK if they're wholly within the image canvas (or overlapping top / left edges), but don't force a redraw when they're overlapping right / bottom margins of the image canvas window.
The image canvas now correctly redraws itself when other X or Wine windows obscure it and then move away, or I switch desktops etc.
I've seen one total application lockup when moving another X window across the front of the PSP ones managed by Wine, but I need to do some more investigation there to try and figure out what symptoms cause it though.
Still, looking good on the whole, so a big thanks to whoever's been messing with the redraw code lately! (Vitaly?)
cheers
Jules