use System.ComponentModel

class Test

	var _visited as bool

	def main is shared
		Test().run
		
	def run
		assert not _visited
		using c = Component()
			c.disposed += ref .componentDisposed  # .error. listen
			c.disposed -= ref .componentDisposed  # .error. ignore
		assert _visited
		
	def componentDisposed(sender as Object, args as EventArgs)
		_visited = true