title: Validating fonts and colors NSToolbarItem items
body: <p>Using Cocoa with latest SDK on OSX 10.6.6 </p>
  
  <p>I have an NSToolbar with custom toolbar items and also the built in fonts and colors NSToolbarItem items (NSToolbarShowFontsItem and NSToolbarShowColorsItem identifiers).</p>
  
  <p>I need to be able to enable/disable those in various situations. Problem is  <code>validateToolbarItem:</code> is never called for these items (it is being called for my other toolbar items).</p>
  
  <p>The documentation is not very clear about this:</p>
  
  <blockquote>
    <p>The toolbar automatically takes care
    of darkening an image item when it is
    clicked and fading it when it is
    disabled. All your code has to do is
    validate the item. If an image item
    has a valid target/action pair, then
    the toolbar will call
    NSToolbarItemValidation’s
    validateToolbarItem: on target if the
    target implements it; otherwise the
    item is enabled by default.</p>
  </blockquote>
  
  <p>I don't explicitly set target/action for these two toolbar items, I want to use their default behavior. Does it mean I can't validate these items? Or is there any other way I can do this?</p>
  
  <p>Thanks.</p>