DNS choices upon install or not?

I’m confused about DNS changes for installing Ice Dragon. Is the zipped portable edition supposed to give a choice to use Comodo Ice Dragon’s DNS upon unpacking or installation? How do we choose? If we choose (or not given the choice), then will Ice Dragon change our computer’s DNS settings for the whole computer, or will the DNS which Ice Dragon sets be JUST for Ice Dragon and leave the other browsers with the currently set DNS choice? How do we control this exactly? When I used and updated Comodo Dragon (not the Ice Dragon), the choice was always offered, and as far as I knew, I accepted the Dragon’s DNS offering and that Comodo DRAGON left the rest of the DNS for the computer alone.

How do I understand this, and control this, and later undo whatever DNS things that Ice Dragon does?

(I made a test ‘install’ of portable Ice Dragon onto a flash drive but no choice about DNS was given).

Comodo Secure DNS hasn’t been an option during the installation of IceDragon for a long time now. It was available during the first release of IceDragon (version 13.0) on a system-wide basis only. If I remember correctly, it was changed to ‘Enable Comodo Secure DNS in IceDragon only’ as a feature in IceDragon version 14.0. I don’t remember when it was taken out.

If you want to change DNS settings on a system-wide basis for Windows 7 & other versions of Windows, go here for the procedure: Configuring Secure DNS for Windows 7 and Other OSs | Comodo
or here for more details on Windows 7 procedure: How to Enable and disable Comodo Secure DNS Service for Windows 7 and Vista

If you didn’t want to manually change the settings, use this program to easily change the DNS settings on a system-wide basis and to pick from a list of other DNS choices: Dns Jumper v2.3 - A Free DNS Changer

Depending on your location (among other things), you may find that the Comodo Secure DNS is noticeably slower than your current DNS. If that is the case, you may want to try out the following program to find a faster DNS:

If you find a faster DNS, you should google it to see if it offers the security you’re looking for.

gs22, thanks.
Now, not having the choice offered during installation is not a problem and does not bother me. Websites and searches are fine. Small or so trouble with slowness of browser response, but Firefox ESR is worse (doing these on Windows Vista). Ice Dragon on the machine is the portable edition.

I plan NOT to make any DNS selections, but to just let the computer do what it expects to do according to whatever it is with DNS.