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

OpenRA.Game/Orders/UnitOrderGenerator.cs

@@ -96,10 +96,10 @@ namespace OpenRA.Orders
 
 			var o = OrderForUnit(underCursor, target, mi);
 
-			if (o == null || o.Trait is IMove)
-				return true;
+			if (o != null && o.Order.OverrideSelection)
+				return false;
 
-			return false;
+			return true;
 		}
 
 		static UnitOrderResult OrderForUnit(Actor self, Target target, MouseInput mi)

OpenRA.Game/Traits/TraitsInterfaces.cs

@@ -79,6 +79,7 @@ namespace OpenRA.Traits
 		int OrderPriority { get; }
 		bool CanTarget(Actor self, Target target, List<Actor> othersAtTarget, TargetModifiers modifiers, ref string cursor);
 		bool IsQueued { get; }
+		bool OverrideSelection { get; }
 	}
 
 	public interface IResolveOrder { void ResolveOrder(Actor self, Order order); }

OpenRA.Game/Widgets/WorldInteractionControllerWidget.cs

@@ -68,9 +68,15 @@ namespace OpenRA.Widgets
 
 				dragStart = xy;
 
-				// Place buildings
-				if (!useClassicMouseStyle || !World.Selection.Actors.Any())
+				// Place buildings, use support powers, and other non-unit things
+				if (!(World.OrderGenerator is UnitOrderGenerator))
+				{
 					ApplyOrders(World, xy, mi);
+					dragStart = dragEnd = null;
+					YieldMouseFocus(mi);
+					lastMousePosition = xy;
+					return true;
+				}
 			}
 
 			if (mi.Button == MouseButton.Left && mi.Event == MouseInputEvent.Move && dragStart.HasValue)
@@ -114,8 +120,6 @@ namespace OpenRA.Widgets
 						World.Selection.Combine(World, newSelection, mi.Modifiers.HasModifier(Modifiers.Shift), dragStart == xy);
 					}
 				}
-				else if (useClassicMouseStyle)
-						ApplyOrders(World, xy, mi);
 
 				dragStart = dragEnd = null;
 				YieldMouseFocus(mi);