Challenge: Add Menu Item Validation
Add menu item validation to disable the Configure Die menu item if no DieView is presently first responder. If you need to, refer back to the section in Chapter 21.
One hint: the is operator returns true if the left operand is of
the same type as the right operand.
Get Cocoa Programming for OS X: The Big Nerd Ranch Guide now with the O’Reilly learning platform.
O’Reilly members experience books, live events, courses curated by job role, and more from O’Reilly and nearly 200 top publishers.
