Controller Editor 
Controllers represent the active part of a Web Dynpro application. They have a Context and a number of attributes, Events and Methods. The individual parts of all component-global controllers (component controllers including interface controller parts and custom controllers) can be created and maintained in this area of the Web Dynpro Explorer. First of all, select the controller. You do this by double-clicking the controller in the object list.
Caution
If you want to maintain the context of a view controller or a window controller, however, double-click on the relevant object list entry to branch to the View Editor or to the Window Editor.
More information about the properties of the different controllers of a component: Controllers of a Component.