Stephan , I solved this specific problem doing this.
QCGroupedFormRenderer renderControl:id: is used.
renderContentOn:ajaxScript: and then renderEditorOn:ajaxScript; and renderInputOn:ajaxScript: are in the message chain .
What i did was create renderInputOn:ajaxScript: into MAJQDateInputComponent
renderInputOn: html ajaxScript: aScript
self renderInputOn: html.
It works very well now.
I am newbie to develop Seaside , Magritte and QCMagritte apps then i hope everyone express their opinion about this workaround.
TIA
<magritteDescription>
^ MADateDescription new
priority: 200;
beRequired ;
label: 'Vencimiento';
accessor: #vencimiento;
default: ( Date today + 30 ) ;
componentClass: MAJQDateInputComponent ;
comment: 'Fecha de vencimiento de la lista de precios';
yourself