Bug 334644 Cannot manually un/render a window that's directly under the application
Setting the 'toBeRendered' flag for a window that's a direct child of an application does nothing. The workaround is to manually de/construct it via the IPresentationEngine.
bundles/org.eclipse.e4.ui.workbench.swt/src/org/eclipse/e4/ui/internal/workbench/swt/PartRenderingEngine.java
return builder.toString();
	}
	public Object createGui(MUIElement element, Object parentWidget,
			IEclipseContext parentContext) {
		if (!element.isToBeRendered())
			return null;
		if (!renderedElements.contains(element))
			renderedElements.add(element);
		
		if (removeRoot != null) {
			return null;
		}
		if (element.getWidget() != null) {
			if (element.getWidget() instanceof Control
					&& parentWidget instanceof Composite) {
				Control ctrl = (Control) element.getWidget();
				if (ctrl.getParent() != parentWidget) {
					ctrl.setParent((Composite) parentWidget);
				}
			}
			
			if (element.getParent() instanceof MUIElement) {
				MElementContainer<MUIElement> parentElement = element
						.getParent();
				AbstractPartRenderer parentRenderer = getRendererFor(parentElement);
				if (parentRenderer != null)
					parentRenderer.childRendered(parentElement, element);
			}
			return element.getWidget();
		}