can't find display controls, synaptic broken filter is broken.

[Capricorny]

Can you tell exactly why you post this in the "News" section? Why do you think this has any generality for Knoppix 7.6.1? "General support" is a much better place for this, IMHO.

1. on one of my systems I run a laptop display and a wide external monitor. Windows 8.x has no problem automatically sizing both displays. But in Knoppix, the external monitor is only showing a portion of the desktop. I've looked all over, and haven't been able to find a tool to adjust the screen resolution or otherwise fit the desktop to the screen. the result is that I have to fish blindly for the start icon, and I can't see the bottom taskbar, and basically the desktop is chopped off on all sides.

Is there I tool I haven't recognized that can help me with this?

You must try out all possibilities in ARandR, the program behind the monitor icon on the taskbar, first. That's the default resolution manager - remember to 'Layout,Apply' the choices you make. Maybe you already have, but you must tell us about it. Also details about the hardware are useful. Did you try googling for 'ARandR' plus your hardware setup?

2. I tried to install UFRaw using synaptic, and it laboured for hours!, and finally presented me with the news that the attempt had failed, and that there were now two broken items that I had to find using the "broken filter." Unfortunately, the "broken filter" doesn't find anything, and so it seems synaptic itself is now broken.

Is there a fix?

I've run into other problems too, but two are probably already enough to get me branded as "troll" again.

First, whenever you suspect something risky ahead, start Knoppix w/o persistence, cheatcode noimage. You can then try out actual changes before committing them to persistent store.
Also, keep a backup of the last working version of your persistent store.

I just tried, from command line

sudo apt-get install ufraw
sudo apt-get install gimp-ufraw

No problems whatsoever. But then, I had issued

sudo apt-get update

in beforehand. In synaptic, you always start with the 'Reload' button. Because Knoppix is a mixture of different Debian release versions, this is particularly important to do. (Not apt-get upgrade!)
My advice is that you start with a new install, but keep a backup of the pristine setup this time.
Also, I have discovered that Knoppix nowadays often leaves the persistence file system with errors.
You should (from somewhere else) try

sudo e2fsck -fy KNOPPIX/knoppix-data.img

and look at the output.
If you regularly find that it is left in a broken state upon normal shutdown, that is very interesting news, I would like you to post about it in this subforum!
Good luck!