Why does pressing Alt +click middle mouse button now drag the timeline?

Why does pressing Alt + click middle mouse button now drag the timeline? This might be a feature of one of the add-on I installed, but I’m not sure which one. I hope to restore it to the default function.

do you have grease pencil tools enabled? It has that function, but you can reassign/deactivate it in the addon prefs.

you are right!!!thx!