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/actions/LinkEditorAction.java
*/
	private void updateLinkingEnabled(boolean toEnableLinking) {
		setChecked(toEnableLinking);
		if (toEnableLinking) {
			
			updateSelectionJob.schedule(BRIEF_DELAY);
			commonViewer.addSelectionChangedListener(this);
			commonNavigator.getSite().getPage().addPartListener(partListener);
		} else {
			commonViewer.removeSelectionChangedListener(this);
			commonNavigator.getSite().getPage()
					.removePartListener(partListener);
		}
	}
	private IStructuredSelection mergeSelection(IStructuredSelection aBase,
			IStructuredSelection aSelectionToAppend) {
		if (aBase == null || aBase.isEmpty()) {
			return (aSelectionToAppend != null) ? aSelectionToAppend
					: StructuredSelection.EMPTY;
		} else if (aSelectionToAppend == null || aSelectionToAppend.isEmpty()) {
			return aBase;
		} else {
			List newItems = new ArrayList(aBase.toList());
			newItems.addAll(aSelectionToAppend.toList());
			return new StructuredSelection(newItems);
		}
	}
 
}