Custom CSS class drops it's effect after project is saved and the class isn't present in the style.css

Wappler Version : 4.7.0
Operating System : windows 10
Server Model: NodeJS
Database Type: none
Hosting Type: local

Video showing the bug

I’ve tried restarting both the app and the OS but the issue persists.

Video tutorial I’ve been following that also shows how it should actually behave (timestamp is set at 20:26)