Why doesn't StackedInline keep the last element?

Question

Django

class SocialInLine(admin.StackedInline):
    model = social_link
    max_num = 2
class EmployeeAdmin(admin.ModelAdmin):
.......
    inlines = [
        SocialInLine
    ]

I enter data:

but why doesn't it save the last element for me?
Django==1.9

Answer 1

You explicitly specified max_num = 2