Designing animations for hidden objects

Hello guys,

This is a problem I faced a few times and maybe there is a better solution than my current one.
Imagine you create a dropdown-menu in a timeline-2 that is only visible from the 2nd frame on plus when a button is triggered.
Afterwards I want to create a new timeline-3 that is based on the opened dropdown-menu. Since the timeline-2 is hidden, it’s not very comfortable to design the new timeline-3.

How do you handle that kind of problem?

Sorry maybe I missed it, but what is your solution?

I just delete all keyframes that makes my object invisible. At the end I have to recreate them.