WeatherCat Version 4.0.0 dev release #9 is now available for testing. See https://athena.trixology.com/index.php?topic=3696.0 for more details and download.
I saved positions for WC and now WC display stays where I want it.
There isn't any application involvement with fast user switching, it's all Apple. I'll collate the information from this thread and pass it on to Apple to see what they say. To reduce the number of variables, please ensure you are running WeatherCat V1.2.3 build 16.HantaYo, I think yours is a different problem - possibly WeatherCat's prefs file isn't writable/readable?