popup at cursor bound to button press

[AndyM48]

I have successfully bound popup at cursor to the key "Super-Space" using the command "sh -c "pkill -u $(whoami) -f menutray -SIGUSR1"" as suggested. However when I try to bind the command to "Super-button1" it does not work. There does seem to be an error generated, but I am not sure that it is related :( :
GLib-GObject-CRITICAL **: g_object_set_data: assertion 'G_IS_OBJECT (object)' failed at /usr/share/perl5/vendor_perl/Gtk3.pm line 1389.
If I change the command to send the TERM signal instead of SIGUSR1, it seems to work.