Does WPF still flow in custom ICommand implementations?

Prior to .Net 4.5, WPF controls used to leak in user implementations ICommandthat did not use the weak event pattern because they did not unsubscribe from the CanExecuteChangedinterface event .

Now we have a class CanExecuteChangedEventManager, and a quick search JustDecompile discovers that clans are of type MenuItemand ButtonBaseuse a dispatcher, thereby avoiding leakage.

Is there a need to use a weak event pattern when creating a custom one ICommand?