The tree view structure can be expanded or collapsed by clicking on the ‘+’ or ‘–’ icons adjacent to each node, in a similar way to navigation within Microsoft Windows Explorer.
Each node that has ‘+’ or ‘-‘symbol next to it can be expanded to show items that exist within that structure. When no symbol exists you have reached the extent of that particular element.
Tree views are a good method of structuring and displaying items so that they can be easily found by working through the organised structure. Good structure can greatly assist with making searches and item location more efficient.