Some buggy behaviour of UI Builder

During my week long of using UI Builder and UI Toolkit, I actually encountered several buggy behaviour.

  1. When adding/removing selector to an element via UI builder, upon hitting save (CTRL+S) it revert back to its original state.
  2. Occasionally, the inspector will bug out, seems like fail to render,
  3. Sometimes it will crash the editor upon double clicking the tab to make it back to normal size (from maximized)
  4. Sometime it will become its own window for no reason

1 and 2 are the more common and frustrating one, especially 1 since it make me unable to progress, is there any solution or similar situation for reference

Hi,
Could you please file a bug report Unity QA: Building quality with passion?