Bug 176764 [Undo] - DeleteResourcesOperation does not handle overlapped selections
In a project, create a folder f1. In f1, create another folder f2. Select f1 and f2 delete The undo fails with a "not enough info to restore" message. The problem is that the resource description for f2 checks to see whether f2's parent is valid, and at the time of the check, f1 has not been restored. Either the validity check needs to be smarter, or else the deletes should be collapsed into just f1.
bundles/org.eclipse.ui.ide/src/org/eclipse/ui/ide/undo/AbstractResourcesOperation.java
}
	/**
	 * Compute the status for creating resources from the descriptions. A status
	 * severity of <code>OK</code> indicates that the create is likely to be
	 * successful. A status severity of <code>ERROR</code> indicates that the
	 * operation is no longer valid. Other status severities are open to
	 * interpretation by the caller.
	 * 
	 * Note this method may be called on initial creation of a resource, or when
	 * a create or delete operation is being undone or redone. Therefore, this
	 * method should check conditions that can change over the life of the
	 * operation, such as the existence of the information needed to carry out
	 * the operation. One-time static checks should typically be done by the
	 * caller (such as the action that creates the operation) so that the user
	 * is not continually prompted or warned about conditions that were
	 * acceptable at the time of original execution.
	 * 
	 * @param allowOverwrite
	 *            a boolean that specifies whether resource creation should be
	 *            allowed to overwrite an existent resource.
	 */
	protected IStatus computeCreateStatus(boolean allowOverwrite) {
		if (resourceDescriptions == null || resourceDescriptions.length == 0) {
			markInvalid();
			return getErrorStatus(UndoMessages.AbstractResourcesOperation_NotEnoughInfo);
		}
		for (int i = 0; i < resourceDescriptions.length; i++) {
			
			if (!resourceDescriptions[i].isValid()) {
				markInvalid();