Bug 327765 EPartService will hide a part of another perspective
bundles/org.eclipse.e4.ui.workbench/src/org/eclipse/e4/ui/internal/workbench/PartServiceImpl.java
IEclipseContext windowContext = window.getContext();
		
		if (windowContext.getParent().getActiveChild() == windowContext && part == activePart) {
			return;
		}
		modelService.bringToTop(part);
		window.getParent().setSelectedElement(window);
		partActivationHistory.activate(part, activateBranch);
		Object object = part.getObject();
		if (object != null && requiresFocus) {
			ContextInjectionFactory.invoke(object, Focus.class, part.getContext(), null);
		}
	}
	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.e4.ui.workbench.modeling.EPartService#getActivePart()
	 */
	public MPart getActivePart() {
		return activePart;
	}
	/*
	 * (non-Javadoc)
	 * 
	 * @see
	 * 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();