1. Install Unity 2023.3.0b3 for scenario week
2. Install UI Toolkit and use UI Builder to try and make a custom slider
3. Click the + button to add a new USS stylesheet in UI Builder
4. Note functionality:

Bug:  If users click the + button to add a new USS stylesheet in UI Builder, it will create the new style, but not add it to the current document. Users must go back and click the + again, and choose to add an existing stylesheet and browse to the newly created file again to add it.

Note: we only had one report of this in the channel - not sure how prevalent it is [https://unity.slack.com/archives/C06CT8REG6T/p1705333842106299?thread_ts=1705264628.158019&cid=C06CT8REG6T]