Forwarded from https://bugzilla.redhat.com/show_bug.cgi?id=588023

Description of problem:
Clicking on email addresses in evolution no longer in F13/evolution 2.30.0 if you are not using the GNOME desktop but KDE, Xfce, LXDE, whatever.

Version-Release number of selected component (if applicable):
evolution-2.30.0-3.fc13.x86_64

How reproducible:
Always

Steps to Reproduce:
1. start evolution 2.30.0
2. click on an email address, ether in the header or the body of a mail
  
Actual results:
An error message appears: "Could not open the link. The specified location is not supported."

Expected results:
Composer window should be opened, not matter what desktop environment you are running.

Additional info:
Both Gnome and the other desktops are set to use evolution for composing email:
$ gconftool-2 -g /desktop/gnome/url-handlers/mailto/command
evolution --component=mail %s
$ cat ~/.config/xfce4/helpers.rc 
MailReader=evolution
$ cat ~/.config/libfm/pref-apps.conf 
[Preferred Applications]
WebBrowser=mozilla-firefox.desktop
MailClient=evolution.desktop
$ grep evolution ~/.kde/share/config/emaildefaults 
EmailClient[$e]=evolution %U

I can compose mail by clicking on an address in the Xfce Terminal or gnome-terminal. Everything works fine, it's just evolution that doesn't work.

I wonder if this is related to https://bugzilla.redhat.com/show_bug.cgi?id=525449. I thought evolution >= 2.28 was using gtk_show_uri to open URLs, has this changed again in 2.30?