Hi Daniele,
when importing a timeline I see no timeline content. This is not for all timelines.
“Your Trigger Selector does not seem to exist on this page or there are no animations on this timeline.”
Trigger Selector does exsist (see Screenshot).
Best,
Ben
I’ve ran through a similar issues in v3.0. If I’m not in the page/template having the animation selector I’m not able to edit the animation. Until v2 even if the selector isn’t present it is possibile to edit.
I would also suggested to add the possibility to switch (optionally) to the previous non focus panel layout. Personally I found more similar to node editor and personally (but it is just my case) i don’t run the timeline visualizer very often, because I check on frontend.
This is happening for more than just importing timelines. I was playing around with SVGs when it happened to me, so I thought maybe it had something to do with that, but it appears to be an issue with trigger selectors in general. I know in previous versions there was an issue with selector IDs not being found in the DOM because of the “add element ID as need” setting in Bricks being switched on, but it happened with a previously working animation so I know the ID exists in the DOM. I can see it being a helpful notification in case the selector accidentally gets deleted or changed, but having all the all timeline settings disappear is a bit extreme.
The error has been fixed and should now be more stable. There was a problem with the sync of the actual GSAP timeline instances. Thanks for reporting! 
Will push 3.0.0-beta.3 soon.
