title: Add button with dynamic menu to emacs's modeline?
body: <p>I'm making my own minor mode for emacs. Now I want to add button to modeline. Click on this button must сause pop-up menu appear. The items of this menu depend on user's actions. I know that there is a way to add a function button to modeline with `minor-mode-alist', but I have no idea how to make dynamic menu.</p>