Previously GDK only made up monitors when it initially found none. Now it
also makes up monitors when it initially finds some, but later fails to get
their informatin in a normal way and finally prunes them out, being left with
zero monitors.
Having zero-length monitor array is unexpected and causes a number
of critical warnings and some critical functionality (such as displaying
drop-down menus) fails in such cases.
Ideally, there might be such a way to interrogate W32 API that produces the
information about non-real (but active) monitors out of it so that it isn't
necessary for us to make stuff up. However, this code is already complicated,
and i am not prepared to dig W32 API to find a way to do this.
This fixes the issues people had when they accessed a Windows desktop via RDP.
https://bugzilla.gnome.org/show_bug.cgi?id=777527
4a5cd127ff