I have dual monitors and it works fine for me, so it is hard for me to debug your situation.

Gossip rests on top of egui/eframe which uses winit which handles windowing.  We don't mess with windowing code, we just utilize the libraries provided.  It sounds like the problem you are experiencing might be at the winit level, so if I were you I would start reading through the issues on the https://github.com/rust-windowing/winit repository and maybe you'll find something.  If you find something that requires a change to gossip code, let me know so I can fix it for everybody.

Also, you might have a window manager issue, or a display driver issue.  I've personally had a similar experience when using linux with an nvidia card in a laptop against two monitors, and I solved it by installing the nvidia drivers. 

 I will read this through egui  and let you know  .. my limited exposure to Rust so far been only CLI  .. egui seems interesting ... so yes .. 

As regards to your dual monitor  .. assuning you are running gnome or xfce  .. do your #gossip  windows align  left  (or right)  with < super + left arrow > or  < super + right arrow > ?  

 

 I use xfce, but I don't seem to have these key mappings.  They don't do anything for me. 

 Oh  .. xfce works like popular tiling windows manager - i3 or sway  .. you can map your keys in the settings but out of the box super + left arrow  is to align the window on left half of the screen .. and super+ right arrow for alinging on the right side  .. 

you can check your jeyboard maps in Settings > windows manager > keyboard   ... and edit the shortcuts there  ..  Its kinda same in gnome and cinnamon too  .. bit here and there