This is a slightly more advanced problem than most of the ones I’ve covered so far, but this saved me so much time and aggravation, I wanted to share how I dealt with this problem in detail. On OS X, Spaces and text expansion software don’t really play nicely. If you switch back and forth ...

Let’s say your Mac should display a screen like this: But instead it looks a bit more like this: Somehow, the “show negative colors” preference has become activated.