Using the AJAX User Picker within the "Add New Permission" section of the admin panel causes the page to become unusable

When typing a name in the "Single user" portion of the "Add new permission" section of the admin browser, the page shifts upwards preventing the user from using the interface

Reproduction:

1. Open the Add New Permission Section
2. Put a dot in the Single User option
3. Start typing a name (ensure that your database has enough names in it such that the ajax user picker becomes quite large when it queries) our jira instance has 400+ users)
4. observe that the page will shift upwards
5. click away from the ajax picker - do not pick a user
6. observe that the page is now unusable.

Note:

My Display size is 1920x1200 and my JIRA Logo Banner is of size: 529pxx64px