This dialog allows you to browse for a node in the tree. The purpose of selecting a node is dependent on the context of the situation. Sometimes you will use this window to select a start node for a find/replace operation. Sometimes you will use this window to select an experiment variable in the Experimenter. You may also select objects or nodes in the Global Variables window.
Select the node you want by clicking on it in the tree view, then click on the Select button. The window will then close and return to the original calling window.