I think what maniacb suggest is worth to try.
In the Personal.xlsb, create a macro something like :
Assign a keyboard shortcut to it. For example : ctlr+w, then save it.
Next time with a condition something like this :
There are 100 opened workbooks in the taskbar while the user is browsing the internet with Firefox.
At the time the user want to comeback to work with Excel,
the user click any Excel workbook in the taskbar then ctrl+w in the keyboard...
the "default" workbook then activated.
Maybe it's not exactly you want, but at least now you don't have to:
stare harder to look for my Workbook1 at the bottom of the WINDOWS screen to reactivate Workbook1
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