[CoLoCo] Help! Currently stuck doing configuration during grub-pc upgrade

[Neal McBurnett]

While doing a routine upgrade, prompted by Update Manager, I was
suddenly faced with a dialog for dealing with a conflict between some
grub-pc config file and my existing config file. After answering a few
questions, I am now stuck in a dialog that I don't know how to answer,
but the "back" button is grayed out. I don't know how to proceed -
scared to give the wrong answer, scared to kill the process, etc.

See this bug for the full description, with a screenshot:
 https://bugs.launchpad.net/ubuntu/+source/grub2/+bug/768013

I want to install some more packages, but while this continues, apt is
locked and I can't....

Any tips would be appreciated.  Not sure how I'll proceed here....
Responses to the bug itself would be most helpful, and I'll see them
right away via email since I'm subscribed to it.

Cheers,

Neal McBurnett                 http://neal.mcburnett.org/