* In a couple of places I had to resort to if(IsHighContrast) but mostly
this is just using system brushes consistently or not assuming black
text.
* The default DockPanel theme doesn't work well, so make a minimal high-
contrast theme for it and assign it everywhere.
* The pipeline flow was using fixed colours, use system brushes for the
different elements and switch based on high-contrast to ensure active
and inactive stages are visible (using ActiveCaption looks bad on
normal themes because it's a big block of colour).
* For some reason the flat toolstrip renderer doesn't handle white-on-
black themes, but the system one does. It's a little clunkier but it
shows up correctly without writing tons of custom painting code.
* Range histogram uses a properly contrasting colour for the border.
* Treelist views use a better system colour for selected rows when
inactive and hovered rows (when high contrast).
* Mesh view grids have a system background instead of white
* Various things (pipeline state, mesh viewe) set text colour when
colourising backgrounds of things instead of assuming black.
* I honestly don't know why this fixes it really. I finally got a
reliable repro which involved somehow scrollbars becoming visible and
creating their window handles in a weird circumstance while dragging
the window off fullscreen, and that causing the window handle create
to fail.
* When jumping between draws the tables are rebuilt which destroys any
vertical scrolling, so we save/restore it which means the same row will
be at the top of the view. If there are fewer resources it'll just be
as scrolled down as possible.
baldurk