I just updated, and I’ve lost a heap of options on the timeline, as well as onion skinning doesn’t show up anymore. I’ve attached what it looks like now. Is this a new issue or something other people have had before?
Grab the separator between the eye icon and the  on the first frame and drag it to the right. The layer name width has just been dragged all the way to the left.
I’ve published a solution here:
I think that after fixing #2436 resizing the window might bring some of these problems
Fixed today with Aseprite v1.2.21