Comment 3 for bug 487314

I confirm the same problem using a Brother MFC-9840CDW with the Brother drivers on 64-bit Karmic (stock System76 factory install).

system-config-printer-common-1.1.12+git20090826-0ubuntu8
system-config-printer-gnome-1.1.12+git20090826-0ubuntu8
system-config-printer-udev-1.1.12+git20090826-0ubuntu8
Linux 2.6.31-17-generic #54-Ubuntu SMP Thu Dec 10 17:01:44 UTC 2009 x86_64 GNU/Linux

I'm not sure "toner" anything has anything to do with it. I installed the printer drivers [1] and when to System > Admin > Printing, select the printer and get properties. That was OK. Then, I changed the device URI and hit apply, at which point the dialog expended way off the screen (too wide, as per above).

[1] Drivers I installed are (have to D/L via browser, wget results in 404):
http://welcome.solutions.brother.com/bsc/public_s/id/linux/en/download_prn.html#MFC-9840CDW
mfc9840cdwcupswrapper-1.0.2-4.i386.deb
mfc9840cdwlpr-1.0.2-4.i386.deb

And FYI I also have these:
brscan-skey-0.2.1-3.amd64.deb
brscan2-0.2.5-1.amd64.deb

mfc9840cdwcupswrapper-1.0.2-4.i386.deb contains (note duplicate files):
$ md5sum $(find -type f)
70b4415b80772a1a8e66fb2d1f123cb1 ./usr/local/Brother/Printer/mfc9840cdw/cupswrapper/cupswrapperSetup_mfc9840cdw
40f6fcbfe11d75b762ee934abd13d362 ./usr/local/Brother/Printer/mfc9840cdw/cupswrapper/brlpdwrapper_mfc9840cdw
2123704b072e0345a16a77a016fb570d ./usr/local/Brother/Printer/mfc9840cdw/cupswrapper/brcupsconfcl1
bc9dd0b62458b34bac3b4fa0207df5d5 ./usr/share/cups/model/brmfc9840cdw.ppd
bc9dd0b62458b34bac3b4fa0207df5d5 ./usr/share/ppd/brmfc9840cdw.ppd

I eyeballed all of them and nothing jumped out at me, but I'm not really familiar with PPDs or CUPS other than as an end-user. If someone can tell me what setting(s) in what file(s) might cause this, I can go back through older drivers and try to spot a change. I did diff mfc9840cdwcups-1.0.0-7.i386.deb against mfc9840cdwcupswrapper-1.0.3-1.i386.deb but again, nothing jumped out at me.

So on one hand this looks like a Brother driver problem, but on the other, system-config-printer should be smart enough not to exceed screen size. I will also bring this bug to the attention of the product managers at Brother.