As this topic got addressed a few times I just wanted to point out that I tested and can confirm, that storing projects also saves the current edit buffers of kits.
That means two things: when switching and saving projects you don’t need to be afraid to loose work on unsaved kits but then you still need to take care of saving kits when exporting sysex data.
It also opens other possibilities, as you can have two saved states on kits in any project. Nice isn’t it?!