
Some settings should have package collections associated with them which can be
installed from with an `install more` entry in their menu. For example, the pdf
reader setting should have an `install more` entry which lists okular, evince
and zathura as options. Options which are already installed should be marked as
such. Keep in mind that zathura isa collection of packages. The marking of the
already instaled packages should be done by just checking all the packages in
the collection for the entry (check how the package check system works by
looking at other package dependencies). 

The same goes for the imave viewer, video viewer, text editor settings

Same also goes for the GTK theme setting. 




