For example, if you were to expand a hierarchy in the web browser, the browser saves those objects in the web page. If you then change something that affects the contents of the hierarchy (hierarchy definition, station configuration, user permissions, etc.) you will not see this change in the browser but will continue to see what is saved to the web page. So you must refresh the web page in order to see those changes. The same is true in Workbench, you must refresh the tree node of the hierarchy space (individual hierarchies cannot be refreshed separately).