Broken app within minutes created if the default page syntax of the wiki is not set to XWiki 2.x

Steps to reproduce:

• go to wiki administration
• In the Edit -> Syntax (see editMarkdown.png  )
  • activate the markdown syntax (or any other)
  • set this syntax as the default syntax for wiki pages
• create a new app within minutes from the applications panel
• add some fields, follow all the steps of the wizard, to the end.

Expected result:

• the application is created and it's possible to create a new page in the application, when the page is created and edited the app form is displayed

Actual result:

• in the edit mode and view mode, the app pages display scripts instead of proper forms
  This is because the sheet of the application is created by app within minutes with the Markdown syntax set (as specified by the "default" setting) but with XWiki 2.x content (not sure if it's 2.0 or 2.1). This is not the case for all the scripts of the application, some are created with the proper syntax set.

Bonus expected result:

• as a user, what I would expect to happen is that if, in my application, I added the document content field (or another textarea field), I can type Markdown in the content field / textarea field.
  If this requires extra work, it can be reported as a new issue, this issue is focused on the fact that the application should work (as in be able to edit and view pages of the app).