Allowing Key.AltMask + Key.Space to open the MenuBar too.

Terminal.Gui/Core/Toplevel.cs

@@ -158,6 +158,7 @@ namespace Terminal.Gui {
 
 			switch (keyEvent.Key) {
 			case Key.AltMask:
+			case Key.AltMask | Key.Space:
 			case Key.CtrlMask | Key.Space:
 				if (MenuBar != null && MenuBar.OnKeyDown (keyEvent)) {
 					return true;
@@ -177,6 +178,7 @@ namespace Terminal.Gui {
 
 			switch (keyEvent.Key) {
 			case Key.AltMask:
+			case Key.AltMask | Key.Space:
 			case Key.CtrlMask | Key.Space:
 				if (MenuBar != null && MenuBar.OnKeyUp (keyEvent)) {
 					return true;