BZR 4022???! That is really really old. I strongly encourage you to update, but you may want to read Library management in KiCad version 5 possibly also Converting KiCad version 4 projects to version 5 (Remap a project), and take a backup of your project of course.
But I think there should be a couple of icons on the left toolbar that displays the zone rendering, you may even need to re-fill the zone. I hardly remember how that was done in the days before v4.