On Apr 3, 2018, at 12:54 AM, Quincey Morris <quinceymorris@...> wrote:

On Apr 2, 2018, at 22:39 , Marco S Hyman <marc@...> wrote:

 I didn’t expect I’d have to quit and relaunch again because I changed one line.   Should have known better.

Xcode 9.x has an intermittent bug where it gets confused about what you’ve changed. (It looks like the actual displayed text is inconsistent with some internal memory representation.) It doesn’t happen often, but when it does, the best solution is to close all open source files, and quitting is the quickest way to do that.