code: def mousePressEvent(self, event):
          
          line_number = self.editor.get_linenumber_from_mouse_event(event)
          shift = event.modifiers() & Qt.ShiftModifier
          self.editor.debugger.toogle_breakpoint(line_number,
                                                 edit_condition=shift)
docs: Override Qt method
  
          Add/remove breakpoints by single click.