Why are UI elements displayed in all scenes?

Question

Unity

The problem is that when I create a new scene and in the new scene I add canvas, and buttons to it, then these buttons are displayed throughout the game, in all scenes, how to fix this?

Answer 1

I see 2 possible problems:
1. Somewhere on the parent UI object hangs Object.DontDestroyOnLoad .
2. You load a new scene in parallel, and the UI is saved, since you have 2 scenes hanging at the same time.