UI Toolkit StyleSheets bugs

Hello,

For several versions of Unity 6, I’ve repeatedly encountered an issue where style classes either get duplicated, transferred between different .uss files, or even deleted altogether. In the attached video, I demonstrate an example where a style class is duplicated.

In this specific case, the steps to reproduce are as follows:

  1. Applied a style to an element and saved.
  2. Removed the style from the element and saved.
  3. Clicked on the style and saved.
    → A duplicate style appeared.

However, this doesn’t happen consistently, but rather regularly and seemingly at random. It is especially frustrating when classes jump between different styles, given that my project contains numerous styles.

This issue is highly disruptive and significantly hinders efficient style management.