Since the mouse pointer is not properly captured inside the application in full-screen mode in multi-monitor setups (many other games have the same problem, sadly), I make use of keyboard-scrolling using WASD a lot. It happens a lot of times (reproducibly, I think) that the “focus” for that is lost, meaning that pressing either of WASD will no longer move the map – until one brings focus back to the map by clicking onto it once.
The is very easy to reproduce, since the map is out-of-focus right after a game was loaded:
Start/Load a game. Try either WASD –> nothing happens. Click onto the map once and then press either WASD –> scrolling works.
The same happens when interacting with some / most / all (?) of the popup menus – I did not investigate in detail when focus is lost and when it is not, but it happens every so often.