title: ValidateMenuItem is not getting called for NSMenuItem
body: <p>Here is my sample class and usage:</p>
  
  <pre><code>@interface CCocoaMenuItem : NSMenuItem 
  {
     someClass *someobj;
  }
  
   - (void)menuEventHandler:(id)target;
  - (void)setEnableItem:(BOOL)nEnabled;
  
  @end
  
  @implementation CCocoaMenuItem
  
  - (BOOL)validateMenuItem:(NSMenuItem *)item {
      // return YES or NO based on some conditions;
  // But this method is not getting called
  
  
  }
  
  @end
   CCocoaMenuItem *dummyItem = [[CCocoaMenuItem allocWithZone:[NSMenu menuZone]] initWithTitle:(NSString*)aStr action:nil keyEquivalent:@""] autorelease];
  [dummyItem setAction:@selector(menuEventHandler:)];
  [dummyItem setTarget:dummyItem];
  </code></pre>
  
  <p>here validateMenuItem is not getting called. I have set the action and target. Target is this class object itself and I have defined validatemenuItem in this class only.</p>
  
  <p>Is there anything I am missing here?</p>