As you can see in the attached video, the playhead (playback) gets very slow / lagging if I move my cursor over the timeline. Also I can't reach steady 60fps or even 40 fps with an empty stage. (!) I have tested this issue on multiple Lenovo laptops with Quadro P2000 / GeForce cards (core I7 and 32GB RAM). Thank you for your help.
Just to be sure, are you on the latest version of Adobe Animate that was released a few days ago? If you are, and you continue to face this issue, I suggest getting in touch with our support team using this link https://adobe.ly/2WYE62m