Bug? with 10.11 Plasma/Plasmoids

[Nigel Ridley]

This is 10.11 Oneiric.

Before I file a bug I want to be able to narrow it down a bit and was wondering if anyone else 
had noticed the following (or similar):

Woke up this morning to no internet connection and a dead plasma-desktop (it was black behind a 
running Thunderbird window). At first I tried 'F2 > plasma-desktop' which sort of worked for a 
moment then got 'stuck'. I couldn't access the 'logout' feature and resorted to 'Alt + Ctrl + F1' 
to get to a tty and issued "sudo halt'. I rebooted the laptop, logged in and the plasma-desktop 
got stuck again with the small 'desktop loading' splash screen stuck in the middle of a half 
loaded desktop (I could see the kicker bar and a couple of non-kde apps running as well as a 
couple of [internet accessing] plasmoids. The internet connection was still down. Couldn't do 
anything - not even 'Alt + Ctrl + F1' so had to hit the power button.
I tried renaming, from tty1, .kde to kdeOLD and then .kdeGOOD to .kde then logged into kde but 
still had the same problems. I then decided to start afresh and renamed.kde to kde01, then logged 
back into a clean plasma-desktop :-)

When the internet connection came back on I then put things back the way they were with my backup 
copy of my original .kde (with all my [internet accessing] plasmoids) and everything was OK again.

So why, when there is no internect connection, and [internet accessing] plasmoids running, does 
plasma-desktop refuse to load properly?
Where would I look for a 'bug' and how to reproduce it?

Nigel

P.S. Sorry for the long explanation.