I have seen different approaches to previews in non-WYSIWYG editors.
One is to have a edit and preview screen side-by-side or like here on stackexchange the preview below the editor.
And the other one only shows edit or preview, never both at the same time.
What influences do they have on the UX?
Is it just that I should use the second one on smaller devices and the first one if I got enough screen estate?