Description of problem: When new DS is crested, it's impossible to add annotations to it.

Version-Release number of selected component (if applicable):

How reproducible: always

Steps to Reproduce:
1. Open DataSources page
2. Create a new DataSource
3. Click "0 annotations" link on DS "Details" tab
4. in opened modal click "Add" button

Actual results: Nothing happens

Expected results: Annotation fields should appear

Additional info: This does not happens if there already are annotations, but if all annotations are deleted from existing DS, they can not be added again.