Lots of times in Stata you want to have two or more do files open at the same time, and you do not want to keep adding new do file editor windows.  You want to split or tile the editor.  I never knew how to do that and there seemed to be no drop-down menu command for that. But I just found out you can.  Christophe Kolodziejczyk’s comment just a few months ago on the thread here:  “At least you can have two do files shown besides each other or stacked. If you [have] several do files opened, you just have to [click and ] drag one do-file and you’ll be asked whether you want to tile it vertically or horizontally. I discovered this by chance actually.”