[Koha] Cataloguing: Fields not working

Hi All, I have added some extra fields into a couple of our cataloguing MARC templates which are for local use, but have come across a tiny problem with them. These fields are set up correctly. But, if you are cataloguing in Koha using the Internet Explorer, Firefox or Google Chrome web browsers it won't allow you to enter anything in these fields. Then, if you are using the Apple Safari web browser it will allow you to enter data into these fields. Does anyone know why this may be happening and possible a fix to it? Best Regards,Joel