Bug 126658 [CommonNavigator] [DND] Complete definition of DND API
bundles/org.eclipse.ui.navigator.resources/src/org/eclipse/ui/internal/navigator/resources/workbench/ResourceDropAction.java
return 0;
	}
	/**
	 * Ensures that the drop target meets certain criteria
	 */
	private IStatus validateTarget(PluginDropAdapter dropAdapter, Object target, TransferData transferType) {
		if (!(target instanceof IResource)) {
			return info(ResourceNavigatorMessages.getString("DropAdapter.targetMustBeResource")); 
		}
		IResource resource = getResource(getCurrentTarget());
		if (!resource.isAccessible()) {
			return error(ResourceNavigatorMessages.getString("DropAdapter.canNotDropIntoClosedProject")); 
		}
		IContainer destination = getActualTarget(dropAdapter, resource);
		if (destination.getType() == IResource.ROOT) {
			return error(ResourceNavigatorMessages.getString("DropAdapter.resourcesCanNotBeSiblings")); 
		}
		String message = null;
		
		if (LocalSelectionTransfer.getInstance().isSupportedType(transferType)) {
			IResource[] selectedResources = getSelectedResources();
			if (selectedResources == null)
				message = ResourceNavigatorMessages.getString("DropAdapter.dropOperationErrorOther"); 
			else {
				CopyFilesAndFoldersOperation operation;
				if (this.lastValidOperation == DND.DROP_COPY) {
					operation = getCopyOperation();
				} else {
					operation = getMoveOperation();
				}