Comment # 4 on bug 920784 from Jean Delvare

(In reply to Wolfgang Rosenauer from comment #2)
> Just installed claws here to see.
> In the settings I've got 
> firefox '%s'
> and executing that with an URL on commandline opens a tab with the %s URL in
> Firefox for me.
> So far cannot reproduce.

Sorry I should have checked this first, but I did not expect it to be
configurable (I thought Claws was asking GNOME to open the link.)

In my settings I have:
firefox -a firefox -remote "openURL(%s,new-tab)"

This setting is not proposed in the drop-down so probably it's an old setting,
as I am a long-time Sylpheed / Sylpheed Claws / Claws Mail user.

If I set instead
firefox '%s'
as the drop-down suggests then links open just fine again.

Thank you very much for the quick resolution :-)