Ordering does not work when overriding the META-class

[donhauser]

I've been searching quite a while to figure out why some of my models worked while others didn't.
By working I mean that you can see the dragging widget.

Finally I figured out that this problem comes from overriding the META class:

This code does not work:

from wagtailorderable.models import Orderable

class MyModel(Orderable):

    # Some fields, panels etc here

    class META:
         verbose_name_plural = "My Models"

This code does work:

from wagtailorderable.models import Orderable

class MyModel(Orderable):

    # Some fields, panels etc here

    # No META field

Extending META (instead of overriding) does work though, so this is probably the best option if you want to set verbose names etc.:

This code does work as well:

from wagtailorderable.models import Orderable

class MyModel(Orderable):

    # Some fields, panels etc here

    class META(Orderable.META): # note the inheritance here
         verbose_name_plural = "My Models"

In general I'm not sure, if this is a bug, I'd rather say this is unexpected behavior.

[kristinriebe]

I also had the issue that I couldn't see the dragging widget in the admin for my models. This issue here got me on the right track, since I am also using the Meta class in my models. However, changing the Meta class to inherit from Orderable.Meta (which sets the default ordering to sort_order) did not change anything for me.

I needed to make sure to use sort_order for ordering in the ModelAdmin class in wagtailhooks.py, as suggested by the README of this project. E.g. this version worked (using wagtial version 2.11.3), even if I specified the Meta class of the model with a different ordering or if I removed the Meta class for my model:

from wagtailorderable.modeladmin.mixins import OrderableMixin
from .models import MyModel

class YourModelAdmin(OrderableMixin, ModelAdmin):
    model = YourModel
    ordering = ['sort_order']

I'd suggest to point it out more explicitly in the documentation that 'sort_order' must be set in ordering for the ModelAdmin class, otherwise the drag'n'drop functionality won't appear.
Also, when sorting the list view in the admin interface by one of the other fields (or even by 'sort_order'), the dragging widget will disappear again. This kind of makes sense, but people may wonder when visiting an admin page like "admin/myapp/model/?o=4.2" why the dragging widget is missing.