No network manager lock icon (for the VPN) in Lubuntu 15.10

[gus]

Hi!
I've upgraded 3 days ago to Lubuntu 15.10 (I was on Lubuntu 15.04 since then).

The network manager icon when I connect to my VPN doesn't appear anymore
(it's like a lock on the normal network manager icon).

I've found a bug report on previous release but the problem apparently came
back...
https://bugs.launchpad.net/ubuntu/+source/gnome-icon-theme/+bug/772709

I'm using the default Lubuntu theme. If I switch to Oxygen theme icon for
example, the problem disappears.