CKSource

To get round the 'RequiredFieldValidator' problem in .NET, I found the following solution:

Add a JavaScript function to the page:

   function FCK_ValidationFix()
   {
        if (FCKeditorAPI && FCKeditorAPI.Instances)
        {
           for (var i in FCKeditorAPI.Instances)
            {
            var anFCK = FCKeditorAPI.Instances[i];
            anFCK.UpdateLinkedField();
            }
        }
   }

To the 'insert' button on the form, add ' OnClientClick="FCK_ValidationFix()" '. This function gets called before ASP.NET's webform validation stuff and ensures that the FCK's hidden input is populated before validation takes place. Then the regular RequiredFieldValidator appears to work just fine.

I've only just discovered this so there may be a good reason why this is a bad idea (also I presume the UpdateLinkedField gets called before submit as well which is redundant). If whoever reads this thinks it's OK, perhaps you'd like to copy it to the content page (which I can't edit as it's locked).

-- Danielrendall