The times on your ruler also disappear. Changing timeline zoom makes them reappear but not subtitles. If you close Shotcut with the timeline floating and then restart, then everything appears in the timeline until you redock. Unfortunately, the high level code we write for this does not know about floating or docked. Maybe we can find some little change to make it work, but it is non-obvious trial-and-error.
OK Thank you, @shotcut. It’s not a BIG deal for me since I don’t usually undock the timeline - I just slipped with my mouse and undocked it by mistake…