Bug 296253 [CommonNavigator] An empty label is not properly shown when it is the only contributed label
tests/org.eclipse.ui.tests.navigator/src/org/eclipse/ui/tests/navigator/LabelProviderTest.java
assertEquals(tlp.backgroundColor, rootItems[0]
				.getForeground(0));
		assertEquals(tlp.font, rootItems[0].getFont(0));
		assertEquals(tlp.image, rootItems[0].getImage(0));
	}
	
	
	public void testSimpleResFirst() throws Exception {
		_contentService.bindExtensions(new String[] { TEST_CONTENT_OVERRIDDEN1,
				TEST_CONTENT_OVERRIDE1 }, false);
		_contentService.getActivationService()
				.activateExtensions(
						new String[] { TEST_CONTENT_OVERRIDE1,
								TEST_CONTENT_OVERRIDDEN1 }, true);
		refreshViewer();
		TreeItem[] rootItems = _viewer.getTree().getItems();
		checkItemsAll(rootItems, TestLabelProviderStyledGreen.instance);
	}
	
	/**
	 * E{low} overrides D{low} overrides B{normal} overrides A
	 * F{high} overrides C{low} overrides A
	 * G{normal} overrides C{low}
	 * B branch has higher priority than C's, and G higher than G, so
	 * order should be B branch (E - D - B) then C branches (F - G - C) then A
	 */
	public void testOverrideChain() throws Exception {
		final String[] EXTENSIONS = new String[] { 
				TEST_CONTENT_TRACKING_LABEL + ".A",
				TEST_CONTENT_TRACKING_LABEL + ".B",