You can make it smaller though Dimitri.
This is a known feature/quirk of Suite, if you toggle the map it will go full screen, and if you switch back to the Units Settings View it won't go back to "windowed", but stay maximized.
One could argue if it should or shouldn't, but if you want (I sometimes do), you just need to use the standard Windows window size icons (top right) to make it smaller again. It just doesn't happen automatically.
