Web Messaging SDK config override not applying to launcher

The launcher icon stays blue even after setting the config object. I’m passing this JSON to the init function:

{
 "launcherPosition": "bottomRight",
 "primaryColor": "#ff0000"
}

But the UI ignores it. Is there a specific property name for the color in the Web Messaging deployment settings? The docs are vague on the exact key. I’ve cleared cache and tried different hex formats. Nothing works.