Starting right now, Excel will let you deselect cells or a range of cells from your current selection. Microsoft has just rolled this out for PC and Mac subscription users of Office 365.

To "unselect" (it's a new word, look it up!) a selected cell, hold down the CTRL button (or Command on a Mac) key and click on the cells you want to deselect. To unselect a range of selected cells, hold down the CTRL (or again, the Command for Mac) key and drag the range you want to deselect, starting from within the selected range.

Don’t get confused with the cell in the top left hand corner of the range selected remaining white! You can have fun experimenting what that looks like when it is de-selected...