In wordpress twenty twelve and lot of other new WP themes, there is automatic menu-toggle for small screens. Sometimes you don’t want that but you want leave your existing menu, just to modify it a bit for android, Iphone etc.
Here is simple solution how to disable that toggle menu.
Open CSS file.
Search for line:
/* Minimum width of 600 pixels. */
Bellow that, first line is set to:
@media screen and (min-width: 600px)
Just change that 600px to 100px and update the file. You should see your normal menu again even on smaller screens.