nm-applet running, indicator not in taskbar- new behavior in 16.04

On Lubuntu 16.04, within the last week the nm-applet indicator disappeared from the taskbar even tho LXTask shows it running, and the wifi connection works as usual. The missing indicator is a new behavior- it has run fine for ~6 months since OS install. At first look, nm-applet was not in LXSession core applications and when I clicked Reload, the indicator came back on the panel for a couple hours, then it disappeared again. I went back to LXSession, reloaded again (no change); then manually added it to startup appl's + reboot - no joy.

After reading here, I edited /home/*****/.config/autostart/nm-applet.desktop . NotShowIn=KDE;GNOME; also had LXDE;. I removed LXDE;, saved, + reboot - no change.

In terminal $ nm-applet returns:

** (nm-applet:#####): WARNING **: Error retrieving accessibility bus 
address: org.freedesktop.DBus.Error.ServiceUnknown: The name 
org.a11y.Bus was not provided by any .service files

##### is a 4 or 5 digit number which gets higher when I do the command again.

$ sudo nm-applet returns the above, plus:

(nm-applet:#####): Gdk-CRITICAL **: gdk_window_thaw_toplevel_updates: 
assertion 'window->update_and_descendants_freeze_count > 0' failed

I tried reinstalling lxpanel-indicator-applet-plugin. I've found posts suggesting installing other network monitor or indicator packages + have tried several, with no success. But the indicator worked fine for many months, LXTask shows nm-applet running, something removed nm-applet from LXSession, and added LXDE to NotShowIn in 'autostart/nm-applet.desktop`. These things suggest the answer is more likely to be fixing nm-applet, indicator, or environment, rather than adding something else. I have read there was a bug with nm-applet in 14.04 but that appears to be fixed a year or more ago.

Thanks.

Solution 1:

3 things fixed this.

1. This error:

** (nm-applet:#####): WARNING **: Error retrieving accessibility bus address: org.freedesktop.DBus.Error.ServiceUnknown: The name org.a11y.Bus was not provided by any .service files

... was fixed by installing at-spi2-core from Synaptic Package Manager.
Reference: https://github.com/NixOS/nixpkgs/issues/16327

2. Then in /etc/xdg/autostart/nmapplet.desktop, I changed Exec=nm-applet to dbus-launch nm-applet.
   After manually restarting nm-applet in a terminal window with dbus-launch nm-applet, the wifi indicator applet appeared in the taskbar again. But it did not autostart after a reboot.

3. So in Settings > Default Applications for LX Session, in the Autostart tab, I changed nm-applet to dbus-launch nm-applet.

Then the applet autostarted, and the indicator autostarted.

Reference for 2. and 3. : http://askubuntu.com/questions/592406/nm-applet-wifi-issues-on-lubuntu-14-04