code: def mousePressEvent(self, event):
          
          if self.mode == BuildMode:
              super(StimulusView, self).mousePressEvent(event)
          else:
              # select and de-select components
              index = self.indexAt(event.pos())
              if index.isValid():
                  self.selectionModel().select(index, QtGui.QItemSelectionModel.Toggle)
                  comp = self.model().data(index, AbstractDragView.DragRole)
                  self.componentSelected.emit(comp)
                  self.hintRequested.emit('Click components to toggle more members of auto-parameter\n\n-or-\n\nEdit fields of auto-parameter (parameter type should be selected first)')
docs: In Auto-parameter selection mode, mouse press over an item emits
          `componentSelected`