Bug 327820 Active part stack is not highlighted in a newly opened perspective
1. Run on a new workspace. 2. Activate the 'Outline' view. 3. Window > Open Perspective > Debug 4. The 'Outline' view is active but its tab folder is not coloured blue.
bundles/org.eclipse.e4.ui.workbench/src/org/eclipse/e4/ui/internal/workbench/PartServiceImpl.java
* org.eclipse.e4.ui.workbench.modeling.EPartService#deactivate(org.eclipse.e4.ui.model.application
	 * .MPart)
	 */
	public void deactivate(MPart part) {
		MElementContainer<MUIElement> parent = part.getParent();
		MPart oldSelectedElement = (MPart) parent.getSelectedElement();
		if (oldSelectedElement == part) {
			parent.setSelectedElement(null);
			internalFixContext(null, oldSelectedElement);
		}
	}
	private MPartDescriptor findDescriptor(String id) {
		for (MPartDescriptor descriptor : application.getDescriptors()) {
			if (descriptor.getElementId().equals(id)) {
				return descriptor;
			}
		}
		return null;
	}
	private MPart createPart(MPartDescriptor descriptor) {
		if (descriptor == null) {
			return null;
		}
		MPart part = BasicFactoryImpl.eINSTANCE.createPart();
		part.setElementId(descriptor.getElementId());
		part.getMenus().addAll(EcoreUtil.copyAll(descriptor.getMenus()));
		if (descriptor.getToolbar() != null) {
			part.setToolbar((MToolBar) EcoreUtil.copy((EObject) descriptor.getToolbar()));
		}
		part.setCloseable(descriptor.isCloseable());