A MacRuby example of a custom view in the status bar, with selection highlight.

status_bar_view.rb

class StatusBarView < NSView
  attr_reader :progressIndicator, :statusBarItem
  
  def initWithStatusBarItem(item)
    bar = item.statusBar
    if initWithFrame([[0,0], [bar.thickness, bar.thickness]])
      @statusBarItem = item
      @highlight = false
      
      origin, size = frame.origin, frame.size
      @progressIndicator = NSProgressIndicator.alloc.initWithFrame([[origin.x + 2, origin.x + 2], [size.width - 4, size.height - 4]])
      @progressIndicator.style = NSProgressIndicatorSpinningStyle
      addSubview(@progressIndicator)
      
      @menu = NSMenu.alloc.init
      @menu.delegate = self
      @menu.addItemWithTitle('Quit App', action: 'terminate:', keyEquivalent: '')
      
      @statusBarItem.view = self
      self
    end
  end
  
  def menuWillOpen(_)
    @highlight = true
    self.needsDisplay = true
  end
  
  def menuDidClose(_)
    @highlight = false
    self.needsDisplay = true
  end
  
  def mouseDown(event)
    @statusBarItem.popUpStatusItemMenu(@menu)
  end
  
  def drawRect(rect)
    @statusBarItem.drawStatusBarBackgroundInRect(bounds, withHighlight: @highlight) if @statusBarItem
  end
  
  def startAnimation
    @progressIndicator.startAnimation(self)
  end
  
  def stopAnimation
    @progressIndicator.stopAnimation(self)
  end
end