Sometimes IS has a bug with undo function. It gets crazy, doesn´t undo but does another thing or moves everything, or just loses the design.
This is a bug I haven´t remember to report, but that’s exactly what is happening to you IMO. It’s the only function I¡ve observed to behave like that. Please, @admin, can you report it to the dev team for us? Thank you!
In the mean time, yes, save, save, save, although it is annoying too as we cannot still resave (saving over an existing proyect), which is a feature we´ve been waiting for. So save, save, but in crucial moments only.
PS: No, there’s no autosave
Yes, a big update is supposedly coming, as we’ve been making many suggestions and they’ve been reported.
You can visit this topic 
: