MyApp is calling TIS/TSM in non-main thread environment

I expect that message is coming from the Main Thread Checker: https://developer.apple.com/documentation/code_diagnostics/main_thread_checker

TIS = Text Input Sources

TSM = Text Services Manager

You're doing something like trying to translate key events to characters on a background thread.

There's a setting in the Scheme editor to make your app pause when it hits such a problem, so you can see the stack trace.

Just to thank you, Ken. This really helped me. I was indeed using a Text Input Source in a background thread to translate key events to characters and vice versa. Apparently, that is a no-no, although it didn't crash my app.

For what it's worth, I don't think this behavior is happening because of the Main Thread Checker. At least in Mojave Beta, I was seeing the message in the console even without the main thread checker enabled.

Just for closure here, jalkut wrote a blog post about how they debugged this.

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