Issue with selecting another notebook

[inJUST 0]

What keyboard button is used to select into a different notebook? In the screenshot I'm highlighted onto "Korean" but it won't let me select the highlighted portion. I tried a multitude of keystrokes including but not limited to: ENTER, RIGHT ARROW, TAB, SHIFT+ENTER

I really try to avoid using my mouse as much as possible, especially when it comes to entering text.