Property Inspector for custom classes

I'd like to use Property Inspector to be able to edit custom classes. From what I can see, this works (i.e., I can type "inspect(obj)" and edit properties) as long as the classes are handle classes, but it doesn't seem as effective as for some built-in classes. For example:

• If I look at Figure of Axes objects in Property Inspector, properties are listed in groups. This doesn't occur for my custom classes even if I inherit matlab.mixin.CustomDisplay and implement getPropertyGroups (which enables grouping of properties in the command window display of a class).
• Figures etc seem to be able to deal with arrays of objects. For my custom class, I see in the top navigation area that I have an array on a field, but it only gives me the first element.
• Editors are sensible for integers, logicals etc. Figures etc have nice specialised editors for colours, fonts, etc. Is there any way that I can reuse those?

[.json]

Actually arrays of objects are fine, I had mistakenly populated the array with a copy of the same object handle rather than deep copies.