Volume window opens when mounted

Close the window before dismounting the volume or ejecting the HD.

Then, something's triggering it outside the normal OS and Finder setup. I have no idea what that could be.

Hmmm! The proverbial missing information. I have the install disk restored on an internal partition and that doesn't happen. Check the window that pops up and ensure there's no efi file displayed. If there is, delete it, close the window, dismount, and remount. Alternatively, you could use CCC to clone the install DVD, just make sure that the window that normally pops up when you insert the DVD is closed before cloning.

Absolutely. I use mine to do installations when beta-testing. Much, much faster than using the superdrive.

Then, I'm out of ideas, since the only time I get the window is when I double-click on the volume icon. What happens if you use Disk Utility to unmount and remount the volume, after closing the window?

see this mac os x hint
http://www.macosxhints.com/article.php?story=2009121606541533

personally, i use the method suggested in the comment in that hint - I prevent the clone of the SL dvd from automatically mounting. I rarely need it and when I do i mount it by hand from disk utility.

Maybe because my install disk volumes are on internal partitions, I don't get the opening window. That said, I prefer MacXperte fix at http://forums.macosxhints.com/showthread.php?t=107282

no, it doesn't matter if the drive is external or internal. it happens to me with internal drives too. but on one of my accounts this does not happen with the clone of the install dvd. I don't know why.

Now, that's interesting, since the two install disk partitions on my internal HD don't exhibit that behavior and I never invoked the bless command.

In that particular case, since you apparently don't have write access to that volume, you'll need to put sudo in front:

*sudo bless --folder /Volumes/Mac\ OS\ X\ Install\ DVD/ --saveX*

and at the Password: prompt, enter your admin password, carefully, since nothing shows up on the screen, and hit the return key.