that's a bit to unclear to help you on.
Like, which other programs did you have running?
What drawingtool were you using?
Chibipaint: if you put it in floating mode, it sometimes automatically locks off.
I have it and so do several other people here.
The best solution against losing a drawing is
save as often as you can.
that's what I do.
It has just happened again..drawing disappeared into fresh air... some thing very suspicious going on here.. I wonder if there is some "hacking" happening!???? ... I wont be drawing on "Drawing Day " if this happens it's a waste of ####### time .. I AM FED UP