Automattic/_s — pull request #200 by angoo (2013-04-18 23:48:59+00:00)
Title: Menu should be always visible in a wide browser window

In a narrow browser window, if you click on the menu button to reveal the hidden menu and then expand the window, the menu disappears.
This is because main-small-navigation class added by js remains on the element container.
Moving .main-small-navigation ul { display: none; } inside @media screen and (max-width: 600px)