Bobbis.net

Every once in a while I find myself working in one part of a document or file and need to refer to another part of the document at the same time. Instead of scrolling up and down finding my place every time, most nice text editors have the option to split your window into sections so you can see more than one part of the document at a time. The most well-known program that has this feature is Microsoft Word.

I found this feature initially in the Terminal application

I also use it constantly in TextWrangler and xCode

Usually this is enabled by an icon in the top of the vertical scroll bar.