Action and field activation

Dialog methods can be used to control action and field activation.

Previous versions allowed to modify directly the 'active' attribute of the underlying DOM node in the AUI tree; This is now forbidden: It is mandatory to use the methods to enable/disable action or fields. The dialog will synchronize the 'active' attribute in the AUI tree according to the value passed to the methods and according to the context (some actions or fields can be automatically disabled).