Okay, you have a file with two tabs and would like to be able to see both tabs at the same time. Sure you could save the spreadsheet and open the saved copy in another window but who has time for that.
Press and hold the ALT and W key at the same time. Release both keys then press the N key.
Ta Da! You now have you one file displayed in two windows. Now you can click on a different tab is each window. Best of all, since it’s still one document, when you make changes on one tab, the change impacts both windows.
Basically when you do this you have the same Excel Workbook shown in a vertical fashion. This lets you view different sections of the same data at the same time.
Need to see three tabs at once? Just do the ALT + W then N again.
You can also select New Window from the View Tab. This does the same as ALT + W then N. Clicking Arrange All will allow you to see the different windows.
The next time the boss and you are working together. Show off and use this trick to ensconce yourself as the Excel expert of your team.