In Django 1.10+:
class MyModelInline(admin.TabularInline):
model = MyModel
classes = ['collapse']
https://docs.djangoproject.com/en/stable/ref/contrib/admin/#django.contrib.admin.InlineModelAdmin.classes
In Django 1.10+:
class MyModelInline(admin.TabularInline):
model = MyModel
classes = ['collapse']
https://docs.djangoproject.com/en/stable/ref/contrib/admin/#django.contrib.admin.InlineModelAdmin.classes