docs: def _viewEntryItem(self, item=None, *dum):
          """Pops up the viewer dialog for the entry associated with the given item.
          If 'item' is None, looks for a selected item in the listview.
          The dum arguments are for connecting this to QTreeWidget signals such as doubleClicked().
          """
          # if item not set, look for selected items in listview. Only 1 must be selected.
          select = True
          if item is None:
              selected = [item for item in self.etw.iterator(self.etw.Iterator.Selected) if item._ientry is not None]
              if len(selected) != 1:
                  return
              item = selected[0]
              select = False;  # already selected
          else:
              # make sure item is open -- the click will cause it to close
              self.etw.expandItem(item)
          # show dialog
          ientry = getattr(item, '_ientry', None)
          if ientry is not None:
              self._viewEntryNumber(ientry, select=select)