[PagePartBundle] Hide pagepart dropdown when there are no options configured

[jverdeyen]

Q	A
Bug fix?	no
New feature?	yes
BC breaks?	no
Deprecations?	no
Fixed tickets	-

Sometimes u use a context as a placeholder (for a very custom context) on a page.
A user can't add any pageparts to it, so there shouldn't be a useless dropdown with no select options.

[jockri]

Btw, you can also use a template file as a region in the backend. This is probably what you are looking for.

name: "Test page"
rows:
    - regions:
        - { name: "region_1", span: 12 }
        - { name: "description", span: 12, template: "YourCompanyWebsiteBundle:Pages:TestPage/description.html.twig" }
        - { name: "region_2", span: 12 }