Created attachment 118280 [details]
xdg-email-try-xdg-open.patch

Currently, xdg-email only supports Thunderbird in generic mode. If x-scheme-handler/mailto is assigned to something else, nothing happens, due to the following code:

    echo $client | grep thunderbird > /dev/null 2>&1
    if [ $? -eq 0 ] ; then
        run_thunderbird "$client" "$1"
    fi

    if [ $? -eq 0 ]; then
        exit_success
    else
        exit_failure_operation_failed
    fi

Unless Thunderbird is the default mail client, the above code will always call exit_success since the previous if statement will set $? to 0.

I have attached a patch that tries to call xdg-open instead. If xdg-open fails to find an e-mail client, it falls through to the browser code.