In Edit Windows you can keep copied texts, templates, parts of file.
When you do an edit operation as copy, paste you copy the text into active edit window or paste the text from active edit window
(if you select some text inside an active edit window then it will pasted).
In addition, you may use drag-and-drop for fast removing and coping parts
of file in any edit window.
Drag and drop
That makes an edit window active press Ctrl and 1, 2 or 3.