Bug 327044 EPartService's hidePart(*) should unset the part's parent element if the part is the selected element
It is not valid to have a selected element that's TBR flag is 'false'.
tests/org.eclipse.e4.ui.tests/src/org/eclipse/e4/ui/tests/application/EPartServiceTest.java
EPartService partService = (EPartService) window.getContext().get(
				EPartService.class.getName());
		Collection<MPart> dirtyParts = partService.getDirtyParts();
		assertNotNull(dirtyParts);
		if (before) {
			assertEquals(1, dirtyParts.size());
			assertEquals(saveablePart, dirtyParts.iterator().next());
		} else {
			assertEquals(0, dirtyParts.size());
		}
		saveablePart.setDirty(after);
		dirtyParts = partService.getDirtyParts();
		if (after) {
			assertEquals(1, dirtyParts.size());
			assertEquals(saveablePart, dirtyParts.iterator().next());
		} else {
			assertEquals(0, dirtyParts.size());
		}
	}
	public void testGetDirtyParts3_TrueTrue() {
		testGetDirtyParts3(true, true);
	}
	public void testGetDirtyParts3_TrueFalse() {
		testGetDirtyParts3(true, false);
	}
	public void testGetDirtyParts3_FalseTrue() {
		testGetDirtyParts3(false, true);
	}
	public void testGetDirtyParts3_FalseFalse() {
		testGetDirtyParts3(false, false);