code: def get_channels(self):
          
          selectedItems = self.idx_chan.selectedItems()
          selected_chan = [x.text().split('—')[0] for x in selectedItems]
          chan_in_order = []
          for chan in self.one_grp['chan_to_plot']:
              if chan in selected_chan:
                  chan_in_order.append(chan)
  
          return chan_in_order
docs: Get the selected channel(s in order).
  
          Returns
          -------
          list of str
              name of each channel (without group), in original record order