All components are defined within a Begin_Com / End_Com statements. For example, a dialog component:
The Dialog component has an ancestor of PRIM_DLG.
The Begin_Com statements is followed by Define_Com statements which define the controls and components which this dialog component uses:
Most of these Define_Com statements will be generated by the WYSIWYG designer.
The Define_Com statements are followed by any event or property definitions for this component:
Lastly, the component's logic is defined within its event, property and method routines. These are defined within their Evtroutine/Endroutine, Ptyroutine/Endroutine or Mthroutine/Endroutine statements.
All routines, except the highlighted event routine, have been shown compressed.
To learn more about any of the points covered in this section, select the statement / command in your source code and press F1 to open its entry in the Technical Reference guide.