Used to switch back and forth between the currently selected sheet, and which ever sheet was last active.
Useful for those times when trying to copy lots of little pieces of information between two sheets, or when trying to quickly compare two sheets.
This should not be mistaken for the built-in alt+tab — that only cycles through all open workbooks… so comparing two out of 6 open workbooks is not fun with alt+tab.
It is glitchy with workbooks auto-created by SAP when exporting data; it sometimes stops working when these workbooks are open.
CALL OUT: Special Thanks to my friend Conner for thinking of this.