Related queston. I am not able to save changes in these fields. Is this connected with my not being able to display TinyMCE here?

What version are you using? There was quite a few bugs in earlier versions of Episerver 7 with xhtml fields that were later fixed...Can you also copy paste the property code?

We are using version 8.11  Here are the fields of interest

  [CultureSpecific]
        [Editable(true)]
        [Display(
            Name = "Lobby Warning Text",
            Description = "Modal Dialog Text",
            GroupName = TabNames.SiteSettings,
            Order = 1400)]
        public virtual XhtmlString ModalDialogText { get; set; }



        [CultureSpecific]
        [Editable(true)]
        [Display(
            Name = "Hatch Act Warning (elections) Text",
            Description = "Modal Dialog Text",
            GroupName = TabNames.SiteSettings,
            Order = 1600)]
        public virtual XhtmlString HatchActWarningText { get; set; }