Bug 139511 [CommonNavigator] getParent() fails in certain cases
In the implementation of getParents(), clients can sometimes fail to return the correct parent with the override cases taken into account. The attached patch fixes these issues, but should be reviewed by the Team Team to ensure that it does not cause any regressions for their cases.
bundles/org.eclipse.ui.navigator/src/org/eclipse/ui/internal/navigator/NavigatorContentServiceLabelProvider.java
* Uses only simple ITreeContentProvider.getParent() style semantics. 
	 */
	private String findText(NavigatorContentExtension foundExtension, Object anElement) { 
		String text = null; 
		INavigatorContentDescriptor foundDescriptor;  
		text = foundExtension.getLabelProvider().getText(anElement); 
		if(text == null && (foundDescriptor = foundExtension.getDescriptor()).getOverriddenDescriptor() != null) {
			return findText(contentService.getExtension(foundDescriptor.getOverriddenDescriptor()), anElement);
		}  
		return text;
	}
	
	/**
	 * Search for image and take overrides into account. 
	 * Uses only simple ITreeContentProvider.getParent() style semantics. 
	 */
	private Image findImage(NavigatorContentExtension foundExtension, Object anElement) { 
		Image image = null;
		INavigatorContentDescriptor foundDescriptor;  
		image = foundExtension.getLabelProvider().getImage(anElement); 
		if(image == null && (foundDescriptor = foundExtension.getDescriptor()).getOverriddenDescriptor() != null) {
			return findImage(contentService.getExtension(foundDescriptor.getOverriddenDescriptor()), anElement);
		}  
		return image;
	}
	
	/* (non-Javadoc)
	 * @see org.eclipse.jface.viewers.IFontProvider#getFont(java.lang.Object)
	 */
	public Font getFont(Object anElement) {