Allow the control group modifier key to be customized.

OpenRA.Game/GameRules/Settings.cs

@@ -82,6 +82,11 @@ namespace OpenRA.GameRules
 		public int SheetSize = 2048;
 	}
 	
+	public class KeyboardSettings
+	{
+		public Modifiers ControlGroupModifier = Modifiers.Ctrl;
+	}
+	
 	public class Settings
 	{
 		string SettingsFile;
@@ -92,7 +97,7 @@ namespace OpenRA.GameRules
 		public GraphicSettings Graphics = new GraphicSettings();
 		public ServerSettings Server = new ServerSettings();
 		public DebugSettings Debug = new DebugSettings();
-		
+		public KeyboardSettings Keyboard = new KeyboardSettings();
 		public Dictionary<string, object> Sections;
 		public Settings(string file, Arguments args)
 		{			
@@ -104,7 +109,8 @@ namespace OpenRA.GameRules
 				{"Sound", Sound},
 				{"Graphics", Graphics},
 				{"Server", Server},
-				{"Debug", Debug}
+				{"Debug", Debug},
+				{"Keyboard",Keyboard}
 			};
 			
 			

OpenRA.Game/Selection.cs

@@ -66,7 +66,7 @@ namespace OpenRA
 
 		public void DoControlGroup(World world, int group, Modifiers mods)
 		{
-			if (mods.HasModifier(Modifiers.Ctrl))
+			if (mods.HasModifier(Game.Settings.Keyboard.ControlGroupModifier))
 			{
 				if (actors.Count == 0)
 					return;