Bug 324839 Secondary part selected by EPS due to initially selected part being hidden and removed does not get rendered
1. Have a stack with two parts in it, the selected one has been rendered, the other one is not. 2. Hide the selected part using the EPS. 3. The other part is now the selected part, but it is not rendered.
bundles/org.eclipse.e4.ui.workbench/src/org/eclipse/e4/ui/internal/workbench/PartServiceImpl.java
for (MInputPart p : getInputParts()) {
			if (inputUri.equals(p.getInputURI())) {
				rv.add(p);
			}
		}
		return rv;
	}
	/**
	 * "Container" here is: 1) a selected MPerspective, or, if none available 2) the MWindow for
	 * which this part service is created, or, if not available, 3) the MApplication.
	 */
	private MElementContainer<MUIElement> getContainer() {
		MElementContainer<? extends MUIElement> outerContainer = (workbenchWindow != null) ? workbenchWindow
				: application;
		
		for (MElementContainer<?> container = outerContainer; container != null;) {
			if (container instanceof MPerspective)
				return (MElementContainer<MUIElement>) container;
			Object child = container.getSelectedElement();
			if (child == null)
				break;
			if (child instanceof MElementContainer<?>)
				container = (MElementContainer<?>) child;
			else
				break;
		}
		return (MElementContainer<MUIElement>) outerContainer;
	}
}