Fixes #604 Toplevel repaint.

[BDisp]

No description provided.

[tig]

I am opposed to hacks like this. I understand that this fixes this one toplevel repaint issue, but it does so by mis-using the way the APIs in the project are designed.

We must fix the underlying design instead. At least that's my opinion.

[BDisp]

Even if we have to repaint the entire window to repaint a small fraction?

[tig]

Note, that this PR does not fix situations where dragging Windows doesn't repaint when the Toplevel that is underneath is NOT Application.Top.

Windows & FrameViews illustrates this.

But this PR fixes the specific issue called out, so we should merge it and open another for this other issue.

[tig]

Nice work. Sorry about pushing back so hard; I hope you understand why.

[BDisp]

Nice work. Sorry about pushing back so hard; I hope you understand why.

Never mind. We'll see that after. Thanks.