After installing Seamonkey its default sensible-browser

Thank you for taking the time to report this issue and helping to make Ubuntu better. Examining the information you have given us, this does not appear to be a bug report so we are closing it and converting it to a question in the support tracker. We appreciate the difficulties you are facing, but it would make more sense to raise problems you are having in the support tracker at https://answers.launchpad.net/ubuntu if you are uncertain if they are bugs. For help on reporting bugs, see https://help.ubuntu.com/community/ReportingBugs#When%20not%20to%20file%20a%20bug.

This is a bug and not a question
where is question i dont see question
in description is written about this bug

Well, it's not a bug in seamonkey then. It sounds like Pidgin isn't using the GNOME settings, but most likely using the alternatives link instead.

I converted it to a question so you could get help changing it back

it is couse before installed pidgin opens link in sensible-browser and by dfault its FF
and after install it opens in Seamonkey so it auto set itself..

Also apport crashes opens Seamonkey but default in preffered applications hasnt been changed. Not at least by me but by seamonkey installation

reproduce- remove purge seamonkey-browser and seamonkey
then open ubuntu-bug someprogramm it opens in another browser..
open pidgin link when its set in pidgin gnome default or manual sensible-browser
they opened in someother browser if u had also chrome then in chrome if not then in FF if u had it
then install seamonekey
ubuntu-bug someprogramm
and pidgin links ones in seamonkey..
but still default application in gnome or xubuntu (exo) settings was other browsers..

heres part of installing seamonkey in terminal

Setting up seamonkey-browser (2.0.10+build1+nobinonly-0ubuntu0.10.10.1) ...
update-alternatives: using /usr/bin/seamonkey to provide /usr/bin/x-www-browser (x-www-browser) in auto mode.
update-alternatives: warning: skip creation of /usr/share/man/man1/x-www-browser.1.gz because associated file /usr/share/man/man1/seamonkey.1.gz (of link group x-www-browser) doesn't exist.
update-alternatives: using /usr/bin/seamonkey to provide /usr/bin/mozilla (mozilla) in auto mode.
update-alternatives: warning: skip creation of /usr/share/man/man1/mozilla.1.gz because associated file /usr/share/man/man1/seamonkey.1.gz (of link group mozilla) doesn't exist.

heres settings and bug opened in seamonkey (see window list)

Thank you for taking the time to report this bug and helping to make Ubuntu better. We are sorry that we do not always have the capacity to look at all reported bugs in a timely manner. There have been many changes in Ubuntu since that time you reported the bug and your problem may have been fixed with some of the updates. It would help us a lot if you could test a current, supported, Ubuntu version. If you can test it, and it is still an issue, we would appreciate if you could upload updated logs by running apport-collect 618872, and any other logs that are relevant for this particular issue.

This is a side effect of the alternatives system. If we drop the priority of seamonkey lower, then another group of users will start to complain when they install other browsers and they now override seamonkey as the default.

The real fix is for applications to not rely on alternatives, as this system really sucks for this sort of thing.

Marking this as Opinion. We're not going to be playing around with alternatives priorities, as it's impossible to please everybody.

I dont want any thing to change on my system on installation.
If i want that i can change on 1st time browser asking or in preffered applications.

This is a good solution. Not making it default on installation but on 1st run to ask to be default.