nm-applet spams errors continously

[Mikko Rantalainen]

nm-applet emits errors to X session error log continuously. Here's summary from my log (with timestamps removed with perl):

$ grep nm-applet .xsession-errors | perl -npe 's/\*\*: \d\d:\d\d:\d\d.\d\d\d: //' | sort | uniq -c
    736 (nm-applet:2575): Gtk-CRITICAL gtk_widget_destroy: assertion 'GTK_IS_WIDGET (widget)' failed
    369 (nm-applet:2575): Gtk-WARNING Can't set a parent on widget which has a parent

The nm-applet should be fixed to correctly use GTK API.

ProblemType: Bug
DistroRelease: Ubuntu 18.04
Package: network-manager-gnome 1.8.10-2ubuntu3
ProcVersionSignature: Ubuntu 5.4.0-77.86~18.04.1-lowlatency 5.4.119
Uname: Linux 5.4.0-77-lowlatency x86_64
ApportVersion: 2.20.9-0ubuntu7.24
Architecture: amd64
CurrentDesktop: MATE
Date: Wed Jul 14 14:21:15 2021
EcryptfsInUse: Yes
IfupdownConfig:
 # interfaces(5) file used by ifup(8) and ifdown(8)
 auto lo
 iface lo inet loopback
InstallationDate: Installed on 2019-01-05 (920 days ago)
InstallationMedia: Ubuntu 18.04.1 LTS "Bionic Beaver" - Release amd64 (20180725)
IpRoute:
 default via 84.251.208.1 dev enp3s0 proto dhcp metric 100
 84.251.208.0/20 dev enp3s0 proto kernel scope link src 84.251.221.37 metric 100
 169.254.0.0/16 dev enp3s0 scope link metric 1000
IwConfig:
 enp3s0 no wireless extensions.

 lo no wireless extensions.
NetworkManager.state:
 [main]
 NetworkingEnabled=true
 WirelessEnabled=true
 WWANEnabled=true
RfKill: Error: [Errno 2] No such file or directory: 'rfkill': 'rfkill'
SourcePackage: network-manager-applet
UpgradeStatus: No upgrade log present (probably fresh install)
nmcli-dev:
 DEVICE TYPE STATE DBUS-PATH CONNECTION CON-UUID CON-PATH
 enp3s0 ethernet connected /org/freedesktop/NetworkManager/Devices/2 Ethernet (RJ-45) 6e83ecef-cf26-3a9b-9c6b-7a0a538d0ba8 /org/freedesktop/NetworkManager/ActiveConnection/27
 lo loopback unmanaged /org/freedesktop/NetworkManager/Devices/1 -- -- --
nmcli-nm:
 RUNNING VERSION STATE STARTUP CONNECTIVITY NETWORKING WIFI-HW WIFI WWAN-HW WWAN
 running 1.10.14 connected started full enabled enabled enabled enabled enabled