Log on to Excel in different IBP systems at the same time

Ever tried to log on in Test and Production at the same time, especially under Windows 8?

Easy if you open two (or more) independent Excel session, be either:

1) RUN --> EXCEL /X

-->

or by

2) click ALT on your key board and hold it and than right-mouse-click on the excel-icon in your task bar.

.

If you did it right, you get a popup you need to confirm.

Than you can log on into a different IBP system, or just have your big non-IBP-excel-file in a different session, so if one of them crashes the other still remains.