In memory of the man who put red and green squiggles under words

Every little thing in a graphical user interface that we take for granted today, no matter how small, was thought up by someone, at some point. Case in point: the little red squiggly lines underneath misspelled words. In one form or another, these are everywhere now, and have just become a regular staple of every single text editing field we encounter every single day and don't stop to think about. Still, they were invented by someone, and we happen to know exactly who that was: Tony Krueger.

In early versions of Word, the Spell Check feature was something that you explicitly invoked, and then you had to sit and wait while the program looked for all your potentially-misspelled words, and then showed them to you one at a time for a decision on what to do for each one. Word did introduce an Auto Spell Check feature to run spell check when the user was idle, so that when you hit the Spell Check button, the results were ready to go. However, the Auto Spell Check was still a blocking operation. As a result, a lot of users turned it off because it always seemed to decide Now would be a good time to spell-check the document" just as you wanted to do something, forcing you to wait for the spell check pass to complete before you could, say, save and exit.

Tony made the spell checker much more unobtrusive so that it didn't interfere with your foreground work. And when it found a problem, instead of waiting for you to trigger a spell check, it immediately drew red squiggles under potentially-misspelled words (and later green squiggles under potential grammatical errors).

Raymond Chen at The Old New Thing

Tony Krueger passed away recently, after, among other things, having worked on an dizzying number of Microsoft Word releases. Imagine coming up with something that seems to basic and elementary to us now, and seeing it spread pretty much everywhere. I wonder what it must feel like to have invented something that seems so simple, most people don't even realise they use it every single day.