Bug 334559 EPartService's part searching path may not include parts outside of the active perspective
bundles/org.eclipse.e4.ui.workbench/src/org/eclipse/e4/ui/internal/workbench/PartServiceImpl.java
* 
	 * @see org.eclipse.e4.ui.workbench.modeling.EPartService#getActivePart()
	 */
	public MPart getActivePart() {
		return activePart;
	}
	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.setContributorURI(descriptor.getContributorURI());
		part.setCloseable(descriptor.isCloseable());
		part.setContributionURI(descriptor.getContributionURI());
		part.setLabel(descriptor.getLabel());
		part.setIconURI(descriptor.getIconURI());
		part.setTooltip(descriptor.getTooltip());