Handles when a thumbnail item is double clicked on.
        
        :param      item | <QListWidgetItem>

def handleThumbDblClick( self, item ):
        """
        Handles when a thumbnail item is double clicked on.
        
        :param      item | <QListWidgetItem>
        """
        if ( isinstance(item, RecordListWidgetItem) ):
            self.emitRecordDoubleClicked(item.record())