Bug 327964 EPartService's hidePart may fail when trying to hide a shared part that's in a shared container
The placeholder retrieval code in the EPartService implementation doesn't go far down deep enough and actually stops at the shared container level. This causes the placeholder of the shared part to not be found.
tests/org.eclipse.e4.ui.tests/src/org/eclipse/e4/ui/tests/application/EPartServiceTest.java
testSavePart_NoHandler(true, false, true);
	}
	public void testSavePart_NoHandler_TFF() {
		testSavePart_NoHandler(true, false, false);
	}
	public void testSavePart_NoHandler_FTT() {
		testSavePart_NoHandler(false, true, true);
	}
	public void testSavePart_NoHandler_FTF() {
		testSavePart_NoHandler(false, true, false);
	}
	public void testSavePart_NoHandler_FFT() {
		testSavePart_NoHandler(false, false, true);
	}
	public void testSavePart_NoHandler_FFF() {
		testSavePart_NoHandler(false, false, false);
	}
	private MPart createSaveablePart(
			MElementContainer<MWindowElement> container, boolean beforeDirty) {
		MPart saveablePart = BasicFactoryImpl.eINSTANCE.createPart();
		saveablePart.setDirty(beforeDirty);
		saveablePart
				.setContributionURI("platform:/plugin/org.eclipse.e4.ui.tests/org.eclipse.e4.ui.tests.application.ClientEditor");
		container.getChildren().add(saveablePart);
		return saveablePart;
	}
	private Save prompt(Save[] candidates, MPart partToTest, MPart part) {
		return partToTest == part ? candidates[0] : candidates[1];
	}
	private void testSaveAll(final Save[] returnValues, boolean confirm,