Selectable CPToolbarItem

//Add the following category to CPToolbar

@implementation CPToolbar (selectables)

- (CPToolbar)initWithSelector:(CPString)anId forWindow:(CPWindow)aWindow
{
  if(self = [self initWithIdentifier:anId])
  {
    var mainBundle = [CPBundle mainBundle],
        image = [[CPImage alloc] initWithContentsOfFile:[mainBundle pathForResource:@"selected.png"] 
                                size:CGSizeMake(44, 57)];
    //- this image does not scale
    //- hack on new property
    self._toolbarSelection = [[CPImageView alloc] initWithFrame:CGRectMake(0.0, 0.0, 52.0, 57.0)];
    [_toolbarSelection setImage:image];
    [_toolbarSelection setTag:SELECTED_TOOLBAR_ITEM];
    [_toolbarSelection setAutoresizingMask:CPViewMinXMargin | CPViewMaxXMargin];
    [aWindow setToolbar:self]
  }
  return self ;
}

-(void)setSelectedToolbarItem:(CPString)aTag
{
  var selectionFrame = [_toolbarSelection frame],
      subviews = [_toolbarView subviews];
  
  if([[_toolbarView subviews] indexOfObject:_toolbarSelection] == CPNotFound)
    [_toolbarView addSubview:_toolbarSelection];
  //- hack to move selection image behind the selected toolbar button
  for(var enumerator = [subviews objectEnumerator], toolbarItemView = nil; toolbarItemView = [enumerator nextObject];  )
  {
    if(aTag === toolbarItemView._toolbarItem._tag)
      break;
  }
  var frame = [toolbarItemView convertRect:[toolbarItemView bounds] toView:_toolbarView];
  
  [_toolbarSelection setFrameOrigin:CGPointMake(CGRectGetMinX(frame) + (CGRectGetWidth(frame) - CGRectGetWidth(selectionFrame)) / 2.0, 0.0)];
}

@end

// create toolbar using new init
var toolbar = [[CPToolbar alloc] initWithSelector:@"Tools" forWindow:theWindow];

// add this line to the callback method
[[sender toolbar] setSelectedToolbarItem:[sender tag]];