(In reply to Alexey Kuznetsov from comment #18)
> I did several tests and now it working, probably it is dropbox hangs the
> system for few minutes during scanning.

OK, so ... can you elaborate a bit on what's working and what's not? Presumably
the "scaling mode" is still required for you? Or are you saying that switching
to 720x400 is still broken, even with the scaling mode = full, but switching
back to 2880x1800 afterwards works OK?