As I already properly use :

Code:
Ext.apply(Ext.MessageBox.YES, {text: 'Oui'});
Ext.apply(Ext.MessageBox.NO, {text: 'No'});


if(Ext.Picker){
    Ext.override(Ext.Picker, {
        'doneText': 'OK',
        'cancelText':'Annuler'
    });
}
I'd like to make work :

Code:
if(Ext.LoadMask) {
  Ext.override(Ext.LoadMask, {
    'msg' : 'Chargement...'
  });
}

Unfortunately if permanently fail... Any hint would be appreciate.

Thank you !