nm-applet non-responsive - network selection, wireless enable all ignored [workaround]

I have experienced this issue three or more times now - that nm-applet ceases to respond to any mouse commands at all - ignoring my selection of an alternative wireless network, refusing to launch the connection editor, and not allowing wireless to be disabled. The menu appears to be responsive but none of the commands are actually run or cause any effect.

So far, I proceeded to a workaround like this (I suspect the modprobe steps are unnecessary).

sudo modprobe -r cp210x
sudo modprobe -r rndis_wlan
sudo modprobe rndis_wlan

sudo modprobe -r iwlwifi
sudo modprobe -r mac80211
sudo modprobe mac80211
sudo modprobe iwlwifi

...and finally...

killall nm-applet

...followed by Alt+F2 and running...

nm-applet

...again.

After these steps, nm-applet became once again responsive.

ProblemType: Bug
DistroRelease: Ubuntu 12.04
Package: network-manager-gnome 0.9.4.1-0ubuntu2.1
ProcVersionSignature: Ubuntu 3.2.0-39.62-generic-pae 3.2.39
Uname: Linux 3.2.0-39-generic-pae i686
ApportVersion: 2.0.1-0ubuntu17.1
Architecture: i386
CRDA: Error: [Errno 2] No such file or directory
Date: Thu Mar 28 14:15:13 2013
InstallationMedia: Ubuntu 12.04 LTS "Precise Pangolin" - Release i386 (20120423.2)
IpRoute:
 default via 10.32.78.1 dev wlan0 proto static
 10.32.78.0/23 dev wlan0 proto kernel scope link src 10.32.78.126 metric 2
 169.254.0.0/16 dev wlan0 scope link metric 1000
MarkForUpload: True
NetworkManager.state:
 [main]
 NetworkingEnabled=true
 WirelessEnabled=true
 WWANEnabled=true
 WimaxEnabled=true
ProcEnviron:
 LANGUAGE=en_GB:en
 TERM=xterm
 PATH=(custom, no user)
 LANG=en_GB.UTF-8
 SHELL=/bin/bash
SourcePackage: network-manager-applet
UpgradeStatus: No upgrade log present (probably fresh install)
nmcli-dev:
 DEVICE TYPE STATE DBUS-PATH
 wlan0 802-11-wireless connected /org/freedesktop/NetworkManager/Devices/5
 eth0 802-3-ethernet unavailable /org/freedesktop/NetworkManager/Devices/0
nmcli-nm:
 RUNNING VERSION STATE NET-ENABLED WIFI-HARDWARE WIFI WWAN-HARDWARE WWAN
 running 0.9.4.0 connected enabled enabled enabled enabled enabled