In a KDE panel, I have configured a window with 6 sensors:

localhost:network/interfaces/eth0/transmitter/data
localhost:network/interfaces/eth0/receiver/data
localhost:network/interfaces/wvlan0/transmitter/data
localhost:network/interfaces/wvlan0/receiver/data
localhost:network/interfaces/eth1/transmitter/data
localhost:network/interfaces/eth1/receiver/data

It works OK when all 3 devices are present (but not necessarily all up).

The problem is - when eth1 is not there (not physically present), the applet
displays the "connect creating" icon and never actually displays anything...

It should recognize the device is not there and display the sensors for devices
that are there.