title: Missing inlines in Django Admin
body: <p>See below for models.py/admin.py</p>
  
  <p>When I try to change or add a FashionMaleModel, the inlines don't appear, but they do in FashionFemaleModel. If I change the order in which the admin sites are registered, putting Male below Female, then the inlines only show up in FashionMaleModel, and not FashionFemaleModel.</p>
  
  <p>Why are my inlines only showing up in one or the other?</p>
  
  <p>Thanks!</p>
  
  <hr>
  
  <p>I've truncated these models because there's a lot. Also, FashionObject/FashionPage are base classes I've created as part of a custom CMS with id, name, publish_date, etc.</p>
  
  <p>models.py:</p>
  
  <pre><code>class FashionModelRole(models.Model):
      title = models.CharField(max_length=255,)
  
  class FashionModelContributor(models.Model):
      role = models.ForeignKey(FashionModelRole)
      person = models.ForeignKey(FashionModelPerson, related_name='contributions')
  
  class FashionModel(FashionObject):
      gender = models.CharField(max_length=1,choices=(('F','Female'),('M','Male')), 
  editable=False)
  
  class FashionExperience(models.Model):
      model = models.ForeignKey(FashionModel, related_name = 'experience')
      division = models.ForeignKey(FashionDivision, related_name = 'levels')
      experience = models.CharField(max_length=1,choices=(('5','Professional'),('4','Advanced'),('3','Intermediate'),('2','Developing'),('1','Recreational'),))
  
  class FashionMaleModel(FashionModel):
      jacket_size = MeasurementField(max_length=6, blank=True, null=True)
  
      def __init__(self, *args, **kwargs):
          super(FashionMaleModel, self).__init__(*args, **kwargs)
          self.gender = 'M'
  
  class FashionFemaleModel(FashionModel):
      dress_size = MeasurementField(max_length=6, blank=True, null=True)
  
      def __init__(self, *args, **kwargs):
          super(FashionFemaleModel, self).__init__(*args, **kwargs)
          self.gender = 'F'
  
  class FashionModelPhoto(models.Model):
      model = models.ForeignKey(FashionModel, related_name = 'photos')
      contributors = models.ManyToManyField(FashionModelContributor, null=True, blank=True)
  </code></pre>
  
  <p>admin.py:</p>
  
  <pre><code>class FashionExperienceInline(admin.TabularInline):
      model = FashionExperience
  
  class FashionModelPhotoInline(admin.TabularInline):
      model = FashionModelPhoto
  
  class FashionDivisionAdmin(FashionPageAdmin):
      def __init__(self, *args, **kwargs):
          super(FashionDivisionAdmin, self).__init__(*args, **kwargs)
  
  class FashionModelAdmin(FashionObjectAdmin):
      def __init__(self, *args, **kwargs):
          super(FashionModelAdmin, self).__init__(*args, **kwargs)
          self.inlines += (
              FashionModelPhotoInline,
              FashionExperienceInline,
              )
  
  class FashionMaleModelAdmin(FashionModelAdmin):
      def __init__(self, *args, **kwargs):
          super(FashionMaleModelAdmin, self).__init__(*args, **kwargs)
  
  class FashionFemaleModelAdmin(FashionModelAdmin):
      def __init__(self, *args, **kwargs):
          super(FashionFemaleModelAdmin, self).__init__(*args, **kwargs)
  
  class FashionModelPersonAdmin(admin.ModelAdmin):
      def __init__(self, *args, **kwargs):
          super(FashionModelPersonAdmin, self).__init__(*args, **kwargs)
  
  class FashionModelRoleAdmin(admin.ModelAdmin):
      def __init__(self, *args, **kwargs):
          super(FashionModelRoleAdmin, self).__init__(*args, **kwargs)        
  
  class FashionModelContributorAdmin(admin.ModelAdmin):
      def __init__(self, *args, **kwargs):
          super(FashionModelContributorAdmin, self).__init__(*args, **kwargs)
  
  admin.site.register(FashionMaleModel, FashionMaleModelAdmin)
  admin.site.register(FashionFemaleModel, FashionFemaleModelAdmin)
  admin.site.register(FashionDivision, FashionDivisionAdmin)
  admin.site.register(FashionModelPerson, FashionModelPersonAdmin)
  admin.site.register(FashionModelRole, FashionModelRoleAdmin)
  admin.site.register(FashionModelContributor, FashionModelContributorAdmin)
  </code></pre>