Commit 14ceb10555699 changed the "Open Calendar" item to open the
"recommended" calendar application rather than the default one to
avoid problems with MIME subclassing (namely falling back to the
default text editor when no calendar app is installed).
With this change however, the application launched does no longer
necessarily match the one configured in Settings, which is unexpected.
To avoid both problems, use the default calendar application again,
but only if it is in the list of recommended applications.
https://bugzilla.gnome.org/show_bug.cgi?id=722333
3e20843d9c