Just to bring this somewhat closer to the original topic, as of commit 9190b56
, we have support for mouse grabbing when mouse control is active on Windows. The default behaviour is still set to no grabbing (it is generally considered bad form for software to demand exclusivity of the shared OS pointer), but you can easily change this by inserting the below line in your .GNUstepDefaults file:
"grab-mouse-on-mouse-control" = YES;
This way you can play fullscreen on multiple monitors without fear of accidentally clicking something outside the game's window while five pirates and three thargoids start opening fire on you.
Edit to add: While the mouse is grabbed you cannot click on anything other than the Oolite window itself, but you can still use Alt-Tab normally, in which case mouse is liberated for normal use again. Turning off mouse control mode will also liberate the mouse and leave it available for normal use.