TIWCGJQGridNavDelFormOptions.OnErrorTextFormat Property
The event (can) fire when error occurs from the ajax call and can be used for better formatting of the error messages. To this event is passed response from the server. The event should return single message (not array), which then is displayed to the user.
published property OnErrorTextFormat: TIWCGJSonFunc index 26 read GetFuncValue write SetFuncValue stored IsFuncStored;