Comment 49 for bug 52670

Is anything wrong with this solution?:

Change the x-www-browser script to first check if the $BROWSER environment variable is set. If it is set, use the browser it says. If not, use the browser specified by debian-alternatives. Then update kcontrol to also change $BROWSER.

Because environment variables can be changed by users, this lets users change their preferred browser without having to sudo edit some script, _and_ there can still be a system default (the one specified by debian alternatives).

I think this is preferable to checking for KDE_FULL_SESSION or the value of DESKTOP_SESSION because that would mean putting a desktop environment specific (KDE) hack into Thunderbird. Then we have to think of submitting a bug to the Mozilla team for what it should do if XFCE is the desktop, or Rox filer is, etc. The above solution gives users will get consistent behaviour even if they do something odd like run kcontrol within Gnome and change the preferred browser setting (this is not unheard of -- e.g. I am going to install kcontrol on my friend's laptop so he can use the GUI font installer since Gnome currently lacks one, and some Gnome users probably install it to change the theme of their QT apps).