WIP: UI input handling.

TestGame/TestGame.cs

@@ -19,7 +19,7 @@ public class TestGame : Game
     {
         InitializeSystemsDefault();
 
-        _uiSystem = new UISystem(new ResourceRef<Style>(Guid.Empty));
+        _uiSystem = new UISystem(Input, ResourceRef<Style>.Empty());
         _uiSystem.RenderDebugRects = true;
 
         _particleSystem = new ParticleSystem();
@@ -78,12 +78,6 @@ public class TestGame : Game
             var lastChild = _container.Children.Last();
             _container.RemoveChild(lastChild);
         }
-
-        if (Input.IsMouseButtonDown(MouseButton.Left))
-        {
-            var mousePos = Input.GetMousePosition();
-            _container.Size = new Rect(mousePos.X, mousePos.Y);
-        }
     }
 
     protected override void Render(double deltaTime)