-r => launch synaptic with repository selection dialog open
#( synaptic -r &>/dev/null )&
will open synaptic, only to change the repositories, nothing more.
I think, apt-sources-update isn't the issues here, but if you think it is. We should move it, what other can't say yet, sorry.
Once Synaptic is opened with this command it is also possible:
to use Synaptic to update;
to use Synaptic to uninstall packages;
to use Synaptic to install new packages.
First I am in a wonder about one point : how come the root password was not prompted there ? Second, if apt-sources-update opens synaptic with just "synaptic" or "synaptic -r" it lacks the "gksu -l " feature which allows starting it as full root :
The new Synaptic we have and thefore : /usr/sbin/synaptic is in the root $PATH and therefore needs full root environment... to avoid the "ldconfig no such command" error message...
This is what I have understood so far.
If you using Update-Notifier for make updates?
There found some issues, where i fixed soon...
I could try to look, but my systems now are very much up to date... except the ones that I need to publish next, but I don't like to fool too much with them.