RichEditor field with MVC validation is still posting

I have a public store form with a tinymce text box.  It is set up with validation for ".Required".

                    <div class="inputs">
                        @Html.LabelFor(model => model.SomeText, new {}, ":")
                        @Html.EditorFor(model => model.SomeText,  "RichEditor")
                        @Html.ValidationMessageFor(model => model.SomeText)
                    </div>

However, if the field is left blank, the page still submits/posts to the server.  ModelState.IsValid is false in the   the ActionResult Edit() method, and the partial view is returned and the page then shows the "field is required" validation message.  But, it should not even be getting posted.  The client side validation works fine for the other fields, it's just the tinymce field that has the problem.   I've tried adding a tinyMCE.triggerSave() in the client side submit-click, and it does not help.   Any thoughts?