Version: (using KDE 4.2.4) Compiler: gcc-4.3.3-r2 OS: Linux Installed from: Gentoo Packages In systemsettings going to General -> Default Applications -> Email Client -> Use a different email client: And pressing the "..." button opens the applications browser. Choosing an application e.g. mozilla-firefox applies the string: "/usr/bin/firefox %U". Only by accident I discovered that it should be %u (stands for mailto: URI). If not corrected it causes the browser to go to "http://www.%u.com/".
The component chooser is not setting the %U (nor any other parameter). It is only copying all the Command entry of the .desktop files that the "Open with" dialog shows. So if "firefox %U" is appearing, it is because that is the Command entry. May be some check could be added to convert %U to %u if that is the case... (for email client at least) Updating the title to reflect the discovery. Regards
The real problem is this kcm should strip "thunderbird %U" (obtained from thunderbird.desktop) to "thunderbird". Copying it as it is will not work. Only the binary name itself is needed.
I can not reproduce in last version. I think it's fixed. Reopen if you can reproduce it