The Design Tree contains two major nodes by default: the QueryPairs Folder and the Query Snippets Folder.
You can create folders or QueryPairs in the tree by right-clicking on a folder. You can also edit the folder properties, Cut/Paste/Copy and Delete folders or QueryPairs, and trigger Design-Time executions or update Query connections.
BEST PRACTICE: Highly Nested Items: Trees, QueryPairs and Snippets. Please note that as with any nesting situation, the amount of work a system has to perform to resolve all nested levels increases dramatically with the degree of nesting. Therefore, the best usage strategy is to employ nesting features (e.g. the level of QueryPair treeview nesting or the level of Query Snippet nesting) with moderation.