menus in multiscreen setups

Using multiple monitors in a Xorg Environment, with one screen above the other, navigating menus with cursor keys always warps the menu to the upper screen.

How do I get rid of this menu warp behavior?

I also get this behavior with Debians ready-to-use FVWM config.

How to reproduce this with Debian Stretch:
0) use a fresh Debian Stretch installation and the default Fvwm configuration which comes with Debian Stretch.

  1. Have a multi monitor setup with 2 monitors connected and manage Xorg with fvwm2.
  2. setup screens with xrandr like so: xrandr --output DISPLAY-1 --above DISPLAY-2
  3. restart fvwm to recognize the new screen setup
  4. on lower screen (DISPLAY-2) open an fvwm Menu (for example press windows-menu key to open the menu)
  5. navigate this menu with cursor keys

When doing 5), the menu warps from lower screen (DISPLAY-2) to the upper screen (DISPLAY-1). The same happens to submenus.

I always tested with intel graphics.
Last fvwm version I tested is 2.6.7. First time I recognized this behavior, was with fvwm version 2.5.x.