Eclipse displays two edit windows at the same time

For beginners Java, to some good code to knock a few times is necessary, but sometimes in a few edit window switch back and forth quite troublesome, online search for a long time, also did not find any magic, as the previous blog reprinted, not very practical. Now tell one of your own accidental discoveries.

Open two edit windows at the same time, click a window, drag to the bottom of the editing window, there will be two two edit window outline, let loose.

Do you think it is very simple, please reprint it. Let all beginners know ....