Menu: Menu should close when a user tabs to next focusable element

What MDL Version are you using? (please be specific, e.g. major.minor.patch)
material-design-lite-1.2.1

What browser(s) is this bug affecting (including version)?
Any browser

What OS (and version) are you using?
OSX, 10.11.6

What are the steps to reproduce the bug? Can you create a plunker/codepen/jsfiddle which reproduces it?
- Open the menus section of getmdl.io: https://getmdl.io/components/index.html#menus-section
- Click on a menu botton to open the menu
- Press tab to move to next focusable element

What is the expected behavior?
The menu should close

What is the actual behavior?
The menu is still open

One more:
After clicking on the button to open the menu, it is not possible to navigate the menu using keyboard.
When a user cliks on the menu button, the first menu item shuld gain focus.