Of course the timer is just to allow slow plugins to decide whether they can handle the barcode payload and be added to the list, it's the paint event which asks each plugin for its icon/text/etc., so what one needs to do is to have the plugin alter its icon/text data to whatever is appropriate and then ask for the correct row of the QTableView to be re-drawn to update that information (e.g. calling update() on the QTableView or perhaps QTableViewItem or somesuch)