It was noticed that if the text area stretcher is attached to a field which belongs to a layout which is not our FormView - the extension fails on the client-side and causes the whole layout to break.

The cause for that is the usage of the form field which is initialised in TextAreaStretcherConnector#initFormView - the field may end up being null, but then in the rest of the class it is used as if it non-null.

The right way of doing it would probably be that the extension does nothing and doesn't show itself if it is not in a Magnolia dialog (all the calculations would anyway be wrong).