Bug: Hamburger menu stays open when switching from landscape to portrait mode

[gregmunt]

Steps to reproduce

1. On mobile, make sure you are in landscape mode.
2. Open the hamburger menu.
3. Without closing the menu, switch to portrait mode.

Expected result

The hamburger menu is closed as a consequence of switching to portrait mode, since it is only valid for landscape mode.

Actual result

The hamburger menu is resized to the full size of the display.