I tried to help - and couldn't.
Until now...
Finally we understand the problem and more importantly the resolution. Vicious Cat has BBC.co.uk as his home page. For some reason when you point your browser (confirmed with Firefox and I.E.) at the BBC webpage when you go back to CB you lose your sidebar as soon as you start fighting again. The only way to resolve this issue is if you close your browser and start again. I've had this problem often and thought it was just me and to be honest it's no biggie - however I don't have the BBC as my home page. If you have it as your home page then there's nothing you can do to avoid losing the sidebar as every time you start your browser it commences action from the BBC and the problem kicks in...
So, Vicious Cat now has a resolution and has changed his home page.
If the BBC has this effect on Carnage Blender then I'm sure there are other sites that cause the same effect. Is there a simple fix, or do we have to live with this problem? Some newbies may switch off imediately if it's not resolved.