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

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