I think a good way to do behaviour for modal popup windows would be to draw a thin gray layer over everything on the screen to make it non-interactive and then overlay a modal on top. This would solve issue #13 because it would mean only the modal window can be interacted with while active. However, the issue with this approach would be that the background cannot be interacted with, so for example, players cannot see planets while modifying drones.
I think a good way to do behaviour for modal popup windows would be to draw a thin gray layer over everything on the screen to make it non-interactive and then overlay a modal on top. This would solve issue #13 because it would mean only the modal window can be interacted with while active. However, the issue with this approach would be that the background cannot be interacted with, so for example, players cannot see planets while modifying drones.