My delete key used to delete backwards all by itself. But now I have to used Shift-Delete, or Control-Delete or Option-Delete with it to get it to delete letters in any word processing document like this. What did I accidentally do? (Using latest Sierra, and recently upgraded the Numbers/Keynote/Pages group) It looks like from my research that the delete key was never supposed to work all by itself to delete backwards. But mine did until sometime this morning.