When you want to see two parts of your spreadsheet at once, New Window is what you want to be using.
Found in the View menu, in the Window Section. (Shortcut keys Alt, W, N)
Activating New Window will open another window to the current workbook almost as if it was another workbook. So now you have two copies of the current workbook and you can arrange to see different parts of the workbook at the same time. I use this a lot; it is so much better than flicking back and forth between sheets.
You can actually use this many times to get multiple instances of the same workbook. Changes you make in one ‘version’ will show up in all the other versions. A number at the top of the screen, where the name of the file is, helps you to know which one you are looking at.
You can then use Arrange All (right next to New Window button on the View menu, shortcut keys Alt, W, A) to see all your spreadsheets at once, or just the windows of the current workbook.
You can now also use ‘Side by Side’ and Synchronous Scrolling (see previous post).
If you want to see other applications as well as your spreadsheet, you can quickly arrange the windows on your screen by hovering your mouse over the “maximise” button in the top right hand corner of your screen and choose the layout that you want.
It is probably best to close the ‘extra’ versions before you close the ‘base’ window, otherwise next time you open the workbook, both versions will open and that can be a bit confusing.