Bug 331010 Track Model-Element contributors
We need to track which bundle contributed an model element to e.g. look up translations in the right package
bundles/org.eclipse.e4.ui.workbench/src/org/eclipse/e4/ui/internal/workbench/PartServiceImpl.java
return true;
			}
		}
		if (container instanceof MPerspective) {
			MPerspective persp = (MPerspective) container;
			for (MWindow dw : persp.getWindows()) {
				if (isInContainer(dw, element))
					return true;
			}
		}
		return false;
	}
	MPlaceholder getLocalPlaceholder(MUIElement part) {
		return modelService.findPlaceholderFor(getWindow(), part);
	}
	public void switchPerspective(MPerspective perspective) {
		Assert.isNotNull(perspective);
		MWindow window = getWindow();
		if (window != null && isInContainer(window, perspective)) {
			perspective.getParent().setSelectedElement(perspective);
			List<MPart> newPerspectiveParts = modelService.findElements(perspective, null,
					MPart.class, null);
			
			if (newPerspectiveParts.contains(activePart)
					&& partActivationHistory.isValid(perspective, activePart)) {
				MPart target = activePart;
				IEclipseContext activeChild = activePart.getContext().getParent().getActiveChild();
				if (activeChild != null) {
					activeChild.deactivate();
				}