I was disappointed when I tried out Cauldron and Mutt didn't have a sidebar anymore (and my sidebar-related directives in ~/.muttrc weren't recognized).  I initially thought it was because the patch hadn't been updated to work with Mutt 1.7+, so downloaded the source, hoping to be able to adapt the patch to Mutt 1.7.2, when I saw that Mutt 1.7 already merged the sidebar patch, but you have to compile it with --enable-sidebar, which it seems that the current spec file isn't doing.  Just a heads-up before Mageia 6 happens: adding --enable-sidebar in the spec file will restore the behavior of Mageia 5's Mutt 1.5.23 (you still have to make it visible in your ~/.muttrc file, so users that don't want it won't be affected).