content's PlaceholderField and related TextPlugin isn't deleted when an Article is removed

[sidneijp]

The Article model has a content field of type PlaceholderField (internally it's a ForeignKey) that is used to receive at least the TextPlugin for the body of an article - the cms_wizards automatically add a TextPlugin if content is filled in the form, indeed.

But I realized that when you remove article(s) on the admin, it's not removing none of those, the placeholder used by the content field and its related plugins.

Try this:

• Create an Article with content
• Note the TextPlugin's id and the Placeholder's id of content field
• Remove the article
• Query for the plugin's id on CMSPlugin model - it'll still there
• Query for the placeholder's id on Placeholder model - it'll still there

I think it's a problem because generates garbage - useless registers - on yout database.

Maybe it's actually a design issue on Django CMS's PlaceholderField that do not delete cascade by default.