Fixes issues with support powers and adds property to all IOrderGenerator classes to determine priority over selection in the left-click order scheme.

OpenRA.Mods.Common/Traits/Air/Aircraft.cs

@@ -302,6 +302,7 @@ namespace OpenRA.Mods.Common.Traits
 	{
 		public string OrderID { get { return "Move"; } }
 		public int OrderPriority { get { return 4; } }
+		public bool OverrideSelection { get { return false; } }
 
 		readonly AircraftInfo info;
 

OpenRA.Mods.Common/Traits/Attack/AttackBase.cs

@@ -194,6 +194,7 @@ namespace OpenRA.Mods.Common.Traits
 
 			public string OrderID { get; private set; }
 			public int OrderPriority { get; private set; }
+			public bool OverrideSelection { get { return true; } }
 
 			bool CanTargetActor(Actor self, Target target, TargetModifiers modifiers, ref string cursor)
 			{

OpenRA.Mods.Common/Traits/Buildings/RallyPoint.cs

@@ -56,6 +56,7 @@ namespace OpenRA.Mods.Common.Traits
 		{
 			public string OrderID { get { return "SetRallyPoint"; } }
 			public int OrderPriority { get { return 0; } }
+			public bool OverrideSelection { get { return true; } }
 
 			public bool CanTarget(Actor self, Target target, List<Actor> othersAtTarget, TargetModifiers modifiers, ref string cursor)
 			{

OpenRA.Mods.Common/Traits/Harvester.cs

@@ -445,6 +445,7 @@ namespace OpenRA.Mods.Common.Traits
 			public string OrderID { get { return "Harvest"; } }
 			public int OrderPriority { get { return 10; } }
 			public bool IsQueued { get; protected set; }
+			public bool OverrideSelection { get { return true; } }
 
 			public bool CanTarget(Actor self, Target target, List<Actor> othersAtTarget, TargetModifiers modifiers, ref string cursor)
 			{

OpenRA.Mods.Common/Traits/Mobile.cs

@@ -619,6 +619,7 @@ namespace OpenRA.Mods.Common.Traits
 		{
 			readonly MobileInfo unitType;
 			readonly bool rejectMove;
+			public bool OverrideSelection { get { return false; } }
 
 			public MoveOrderTargeter(Actor self, MobileInfo unitType)
 			{

OpenRA.Mods.Common/Traits/SupportPowers/GrantUpgradePower.cs

@@ -102,6 +102,10 @@ namespace OpenRA.Mods.Common.Traits
 
 			public SelectTarget(World world, string order, SupportPowerManager manager, GrantUpgradePower power)
 			{
+				// Clear selection if using Left-Click Orders
+				if (Game.Settings.Game.UseClassicMouseStyle)
+					manager.Self.World.Selection.Clear();
+
 				this.manager = manager;
 				this.order = order;
 				this.power = power;

OpenRA.Mods.Common/Traits/SupportPowers/SupportPowerManager.cs

@@ -239,6 +239,10 @@ namespace OpenRA.Mods.Common.Traits
 
 		public SelectGenericPowerTarget(string order, SupportPowerManager manager, string cursor, MouseButton button)
 		{
+			// Clear selection if using Left-Click Orders
+			if (Game.Settings.Game.UseClassicMouseStyle)
+				manager.Self.World.Selection.Clear();
+
 			this.manager = manager;
 			this.order = order;
 			this.cursor = cursor;