If this is the direction that Scribus will be taking in the future, I would like to suggest that a "More..." option is added to the end of the truncated drop-down list to allow the user to temporarily expand the list to show all of the available choices.
This would help to prevent users from thinking that the only possible choices were those that are in the truncated list without having to - somehow - guess that they needed to go into Preferences. Otherwise, new users - or users that don't regularly rummage around in the application preferences - might think that the truncated list was all that was available. The fact that the OP has asked the question shows this has been the case in at least one instance.
If this, or something like it, is not done, Scribus will look less capable to a casual user or reviewer than it actually is.