How to "Send Settings" from "App Setting Editor"?

Have you implemented a onSettingsChanged function?

https://developer.garmin.com/connect-iq/api-docs/Toybox/Application/AppBase.html#onSettingsChanged-instance_function

Thanks! I just did. I'm only calling WatchUi.requestUpdate() but that doesn't seem to have any effect. At least it's not calling onUpdate again.

You added onSettingsChanged to your AppBase, correct?  Not to your view.

Add a println to it to make sure it's being called.

Yes, it's getting called.

Obviously I'm doing something wrong. Application.getApp().getProperty() inside the onUpdate function always seems to retrieve the default value.

Did you rename the app but have the same manifest ID?  Things can get confused.  In the sim do a file>Delete All Apps and try again

Name stayed the same. I tried flushing it as suggested, same result.

How many settings are you using? More than say 100?  Are any of your settings long strings?

Is the timestamp on the .set file for your app changing in the sim's temp directory?

5 settings, the longest string is 32 characters long.

Yes, the timestamp is changing every time i click "Send Settings".

Interestingly I cannot access the watch face from the phone's ConnectIQ app, the watch face's icon is greyed out. In other words I cannot access the watch face's settings nor can I delete the watch face through the phone. Though it works through Garmin Express on the computer. I can change the watch face's settings there and delete the watch face as well.

If you side loaded the watch face, you can't use app settings.  For app settings on a real device it's got to be installed from the app store.

Made a copy of the project with a different name and it's all working now.