When I try (on 4.6.18) to create a new Case, I get an error saying Case Type and Case Start Date are required, but no fields exist on the form to specify these?
I have Case Types defined and enabled at civicrm/a/#/caseType
and I've tried adding a case from the menu Cases » New Case and from the Cases tab.
There's no javascript errors showing, nothing in Drupal's watchdog log. Hmmm. Am I doing something daft?