Investigate layer reordering

[dsizzle]

While trying to exercise the latest code by creating an actual image, I ran into odd behavior with layer reordering. Behaviors I witnessed were:

• Layers that I can’t reorder at all
• Layers moving up when I tried to move them down
• Layers reappearing in the wrong place after I moved them

interestingly the behavior seemed to persist even after restarting ArtPaint (at least with the immovable layer) so perhaps there’s something corrupted in the layer data.

Will investigate more and see if there’s an easy repro case

[dsizzle]

Random thought: is there a difference/broken piece between Added layers and Duplicated layers?

[dsizzle]

I know what the problem is, sort of, but don't know a solution yet. Only layers visible without scrolling work fine. Any layers that require scrolling to access don't work. Seems like "BWindow->findView(BPoint)", despite claiming to find views based on the window coordinates, doesn't find items that are scrolled into view? I think this might need a different solution altogether.

[dsizzle]

I like how QuickLaunch works - that's kind of what I was thinking, using D&D vs. the weird way it currently works.