Switch to side-by-side view

--- a/src/sampleconf/mimeview
+++ b/src/sampleconf/mimeview
@@ -103,9 +103,12 @@
 image/x-ms-bmp = gwenview %f
 image/x-xpmi = gwenview %f
 
-message/rfc822 = thunderbird -file %f
-text/x-mail = thunderbird -file %f
-application/x-mimehtml = thunderbird -file %f
+# Opening mail messages just does not work in general, so let's not show an
+# "open" link by default. Savvy users with a suitable config will be able
+# to set things up, and new users won't get confused
+#message/rfc822 = thunderbird -file %f
+#text/x-mail = thunderbird -file %f
+#application/x-mimehtml = thunderbird -file %f
 
 text/calendar = evolution %f