Bug 500582 - The toBeRenderer flag of Top-Level windows needs to be set 
diff --git a/bundles/runtime/org.eclipse.fx.ui.workbench.renderers.fx/src/org/eclipse/fx/ui/workbench/renderers/fx/DefWindowRenderer.java b/bundles/runtime/org.eclipse.fx.ui.workbench.renderers.fx/src/org/eclipse/fx/ui/workbench/renderers/fx/DefWindowRenderer.java
index b83f5ae..bf26292 100755
--- a/bundles/runtime/org.eclipse.fx.ui.workbench.renderers.fx/src/org/eclipse/fx/ui/workbench/renderers/fx/DefWindowRenderer.java
+++ b/bundles/runtime/org.eclipse.fx.ui.workbench.renderers.fx/src/org/eclipse/fx/ui/workbench/renderers/fx/DefWindowRenderer.java
@@ -970,8 +970,7 @@
 		public void addChildWindow(WWindow<?> widget) {
 			this.windows.add(widget);
 			if (this.initDone && this.stage.isShowing()) {
-				Stage s = (Stage) widget.getWidget();
-				s.show();
+				widget.show();
 			}
 		}
 
@@ -1031,6 +1030,7 @@
 
 			// I don't think sub-windows should be activated
 			for (WWindow<?> c : this.windows) {
+				System.err.println("SHOW CHILD: " + c);
 				c.show();
 				this.eventBroker.send(Constants.WINDOW_SHOWN, this.mWindow);
 			}