I think I have fix. I had the same and very annoying behavior that every new
x11 window or frame appeared 'hidden' and had to brought into view via
RightMouse -> Move followed by cursor keys. I have a four-monitor setup.
It appears that where the 'primary' screen is mattered. My primary screen was
the bottom-right one. Changing that in Windows (right-click Desktop ->
Properties -> Settings; select the top-left window, select 'Use this device as
the primary monitor' and hit Apply) was the key.
Now with the primary window being window 1 at the top-left, all new x11 windows
and frame appear there. Much better!