Bug 326175 WBWRenderer arbitrarily modifies the window's parent's active context chain
The window's parent's context arbitrarily changes its active child to the window being rendered in createWidget(*).
tests/org.eclipse.e4.ui.tests/src/org/eclipse/e4/ui/tests/workbench/PartRenderingEngineTests.java
partB.setToBeRendered(false);
		stack.getChildren().add(partA);
		stack.getChildren().add(partB);
		stack.setSelectedElement(partA);
		wb = new E4Workbench(application, appContext);
		wb.createAndRunUI(window);
		CTabFolder tabFolder = (CTabFolder) stack.getWidget();
		assertEquals(1, tabFolder.getItemCount());
		assertEquals(0, tabFolder.getSelectionIndex());
		partB.setToBeRendered(true);
		assertEquals(
				"Rendering another part in the stack should not change the selection",
				0, tabFolder.getSelectionIndex());
		assertEquals(partA, stack.getSelectedElement());
		assertEquals(2, tabFolder.getItemCount());
		assertNotNull(partB.getObject());
	}
	public void testClientObjectUnsetWhenNotRenderedBug301439() {
		final MWindow window = createWindowWithOneView("");
		MApplication application = ApplicationFactoryImpl.eINSTANCE
				.createApplication();
		application.getChildren().add(window);
		application.setContext(appContext);
		appContext.set(MApplication.class.getName(), application);
		wb = new E4Workbench(application, appContext);
		wb.createAndRunUI(window);
		MPartSashContainer container = (MPartSashContainer) window
				.getChildren().get(0);
		MPartStack stack = (MPartStack) container.getChildren().get(0);
		MPart part = (MPart) stack.getChildren().get(0);