Yesterday I worked on a design for a couple of hours and while I was trying to group 2 cubes with the rest of design Tinkercad would not comply with the group command. I then pressed undo a few times and except for the new cubes all of the rest of the design was gone. I have tried several things now, even waiting a day or so but all I can see in the design are those 2 cubes. I have been using Tinkercad for a while and never bumped into something as frustrating as this. Frankly I can deal with bugs but not the kind that destroys hours of work.