Bug 426578 - BaseRenderer.unbindWidget (NullPointer exception, widget is
null)

bundles/runtime/org.eclipse.fx.ui.workbench.fx/src/org/eclipse/fx/ui/workbench/fx/PartRenderingEngine.java

diff --git a/bundles/runtime/org.eclipse.fx.ui.workbench.fx/src/org/eclipse/fx/ui/workbench/fx/PartRenderingEngine.java b/bundles/runtime/org.eclipse.fx.ui.workbench.fx/src/org/eclipse/fx/ui/workbench/fx/PartRenderingEngine.java
index ac991ba..bfdb44f 100755
--- a/bundles/runtime/org.eclipse.fx.ui.workbench.fx/src/org/eclipse/fx/ui/workbench/fx/PartRenderingEngine.java
+++ b/bundles/runtime/org.eclipse.fx.ui.workbench.fx/src/org/eclipse/fx/ui/workbench/fx/PartRenderingEngine.java
@@ -347,6 +347,8 @@
 				if (element instanceof MContext) {
 					clearContext((MContext) element);
 				}
+				
+				element.setRenderer(null);
 			}
 		}
 	}