T7 - Synaptic fails to run from menu - socket failure?

Hello folks y buenos dias todos el mundo,

new install of Belenos-mini, Synaptic doesn't run from the Menu, it does run from a Terminal prompt, gksu, sudo, pkexec and synaptic-pkexec all authenticate OK.

Yesterday on running Synaptic as above, there were messages "...cannot find accessibility socket..." and "...cannot open /tmp/Knt#nMdsrQ..." but they are not there now...

However, when 'Applying Changes' in a Terminal, this message appears on the first line:

"(synaptic:2708): GLib-CRITICAL **: g_child_watch_add_full: assertion 'pid > 0' failed"... is this non-critical, there seems to be no effect on instrallation/removal of applications and dependencies?

I've removed and installed Synaptic using Apt-get, purged and checked, followed the execution path given in the menu to 'synaptic-pkexec' which runs OK...

...so now I've changed the execution line from 'synaptic-pkexec' to 'gksu synaptic'... the menu now works to run synaptic OK.