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
INavigatorContentExtPtConstants {
	private final IConfigurationElement element;
	private final INavigatorContentDescriptor contentDescriptor;
	private Expression dropExpr;
	CommonDropAdapterDescriptor(
			IConfigurationElement aConfigElement,
			INavigatorContentDescriptor aContentDescriptor) {
		element = aConfigElement;
		contentDescriptor = aContentDescriptor;
		init();
	}
	private void init() {
		IConfigurationElement[] children = element.getChildren(TAG_POSSIBLE_DROP_TARGETS);
		if (children.length == 1) {
			dropExpr = new CustomAndExpression(children[0]);
		}
	}
	/**
	 * 
	 * @param anElement
	 *            The element from the set of elements being dragged.
	 * @return True if the element matches the drag expression from the
	 *         extension.
	 */