Bug 302791 [CommonNavigator] Associated editor does not close when deleting resource (editorInput) through CommonNavigator
bundles/org.eclipse.ui.navigator/src/org/eclipse/ui/internal/navigator/dnd/CommonDropAdapterDescriptor.java
public boolean isDragElementSupported(Object anElement) { 
		return contentDescriptor.isPossibleChild(anElement); 
	}
	/**
	 * 
	 * @param aSelection
	 *            The set of elements being dragged.
	 * @return True if the element matches the drag expression from the
	 *         extension.
	 */
	public boolean areDragElementsSupported(IStructuredSelection aSelection) {
		if (aSelection.isEmpty()) {
			return false;
		}
		return contentDescriptor.arePossibleChildren(aSelection);
	}
	/**
	 * 
	 * @param anElement
	 *            The element from the set of elements benig dropped.
	 * @return True if the element matches the drop expression from the
	 *         extension.
	 */
	public boolean isDropElementSupported(Object anElement) {
		if (dropExpr != null && anElement != null) {
			try {
				IEvaluationContext context = NavigatorPlugin.getEvalContext(anElement);
				return dropExpr
						.evaluate(context) == EvaluationResult.TRUE;
			} catch (CoreException e) {