Undo Bug?

[Diulte]

I spent a few hours getting a marble race scene symmetrical but then i noticed one of the items and my marbles was moved and I thought"Did i -accidentally turn it on?"So I decided to undo it to make it back to its simulation run.(Could of use the arrow thing but I didn't know back then.)But when I kept on undoing it was going back to its original state it didn't work!Instead it delete my level and I didn't save it!Can someone tell me how to fix it and get back my scene please? ='(

[Kilinich]

Get used to it. Regularly save your work, re-start Algodoo after hour of running. There are some memory/resource leak in undo/redo that cause problems.