To delete an ABL trigger, select the trigger name in the 
DB Structure view and choose 
Drop
                    Trigger from the context menu. A dialog prompts you to confirm the
                    deletion.
Note: To delete multiple triggers simultaneously, select the triggers
                    in the DB Structure view. Right-click, and then choose
                        Drop Triggers from the context menu.
For more information, see OpenEdge 
 Development: Programming Interfaces. You can find OpenEdge manuals in the Product Documentation section of the Progress Software Developer's Network 
 Web site.