Tumbleweed installed fresh
E19 Desktop
Deployed in Virtualbox 5 (Don't know if relevant)

If an existing application is positioned along the top edge and a new instance
is invoked from the existing application, the new instance is positioned above
the existing app window which means the new window's chrome is completely
off-screen and inaccessible.

Workaround -
1. If invoking a new instance from an existing window, the existing window must
be at least approx 12 pixels below the top edge.
2. Invoke the new instance from the app bar at the bottom of the screen, then
the dm will position the new instance randomly but so far entirely on screen.