If it helps, if i choose 'Exit Game' that works fine and does exit to desktop as per normal. It's not a big issue, and now i've repeated it a few times i know to work around it.
So some more play-testing bug hunting
In the 'Info Screen' (graph graphic icon top right), once i get to 'Statistics' the menu looks a bit odd (the info does not fit in the menu space) and i can't seem to close it within the game screen or move to other catagories in that menu. Using 'Esc' key does close the menu and takes you back to the game, but if i open the 'Info Screen' again it remains 'stuck' on the 'Statistics' tab. Maybe there is a keyboard shortcut to shuffle through the catagories but i've not found one yet.
You redid a bunch of graphics too, resources etc? Or maybe that was an update to base Dune Wars i never got? Anyway it looks really nice, loving the ambience, thank you very much for the obvious hard work that went into it