Bug 16308 [DND] dnd from os to navigator shows an incorrect icon
smoke test for 0518 it shows a move icon although move will not happen
bundles/org.eclipse.ui.views/src/org/eclipse/ui/views/navigator/NavigatorDropAdapter.java
if (returnCode[0] == ALL)
			alwaysOverwrite = true;
		return returnCode[0];
	}
	
	/**
	 * This method is used to notify the action that some aspect of
	 * the drop operation has changed.
	 */
	public boolean validateDrop(
		Object target,
		int dragOperation,
		TransferData transferType) {
		if (dragOperation != DND.DROP_NONE) {
			lastValidOperation = dragOperation;
		}
		if (super.validateDrop(target, dragOperation, transferType)) {
			return true;
		}
		return validateTarget(target, transferType).isOK();
	}
	
	/**
	 * Ensures that the drop target meets certain criteria
	 */
	private IStatus validateTarget(Object target, TransferData transferType) {
		if (!(target instanceof IResource)) {
			return info(ResourceNavigatorMessages.getString("DropAdapter.targetMustBeResource")); 
		}
		IResource resource = (IResource) target;