Fix PHPUnit tests: "FieldGroupUiTest" is randomly failing

Thanks, we indeed need to fix that. My impression is that some days or weeks ago the test were green consistently. Any ideas for the reasons?

They are currently also green. Its random ajax test behavior.

Yup, the 4.0.0 is green currently... crazy. Any ideas welcome how to stabilize this.

So.... it some kind of race condition perhaps from these two?

      $page->pressButton('Save and continue');
      $page->pressButton('Create group');