Merge branch 'master' of https://github.com/UnityTech/UIWidgets

Runtime/engine/UIWidgetsPanel.cs

             get { return this._displayMetrics.viewInsets; }
         }
 
+        protected override void OnDisable() {	
+            D.assert(this._windowAdapter != null);	
+            this._windowAdapter.OnDisable();	
+            this._windowAdapter = null;	
+            base.OnDisable();	
+        }
+        
         protected virtual Widget createWidget() {
             return null;
         }

Runtime/ui/painting/canvas_impl.cs

             foreach (var subLayer in layer.layers) {
                 cmdBuf.ReleaseTemporaryRT(subLayer.rtID);
             }
+            
+            if (layer.rtID == 0) {
+                // this is necessary for webgl2. not sure why... just to be safe to disable the scissor.
+                cmdBuf.DisableScissorRect();
+            }
         }
 
         void _clearLayer(RenderLayer layer) {