When i m drawing or opening a project some parts of my drawing disapear, this is rlly frustrating because hours of work disapear, and i don tknow why,....
In my explorer I see for example my drawing, but when i open it parts are gone, I dont want to open now my project anymore because i m afraid of loosing more work

Sometime when I draw and change to an ereaser and back to brush and i draw over lines before the ereaser it ereases little boxes from my scetch.