I had a similar problem, but that was where I use opera as my browser, but if I clicked a link, it would only open the epiphany browser (which I think is the gentoo/gnome default).
Anyway, I cured this problem by putting this
at the bottom of a file called prefs.js
Initially I couldn't find that, but eventually, I opened konqueror (a kde user obviously) and on the "view" drop down, enabled "show hidden files", which showed me /home/john/.thunderbird (notice the . before thunderbird, that indicates it's normally a hidden file).
Then I had to check through that, and found a directory in there called mb4eu9d7.default - now I don't know if yours would be the same, but I think you may find that it will end in .default
I had to just add the code listed above (you should just have to copy and paste), and change the "firefox" to "opera" and now when I click a link I get opera.
I suspect if you check the file, you'll find that the above code isnt' there (mine wasn't) and obviously your suse won't just open a default system browser, at least I was able to open epiphany, but I then couldn't click/open any links within the link!
Maybe that'd help (should do)