network-applet-manager doesn't build anymore on slackware64-current, it doesn't see NetworkManager-1.12.0, see below the message during "SlackBuilding":
--------------------
checking for GTKDOC_DEPS... yes
checking for LIBNM_GLIB... no
configure: error: in `/tmp/network-manager-applet-1.8.14':
configure: error: No package 'NetworkManager' found
No package 'libnm-glib' found
No package 'libnm-util' found
No package 'libnm-glib-vpn' found

Configure with --without-libnm-gtk if you do not need the legacy library
See `config.log' for more details
----------------------

I'm seeing the same thing except that I'm trying to build Willy's CinnamonSlackBuilds. It will no longer build Cinnamon because libnm-glib and libnm-utils are missing.

You can rebuild NetworkManager and add the option " --with-libnm-glib ", or if Pat would be so kind as to build it with it.

thanks I'll try.

that's ok with your advice it works now.
Thanks.