How do I undo deleting a block?
Immediately after you delete a block, a box will pop up asking you if you would like to undo your action. Click the “Undo” option for the block to reappear in its previous place.
To find and recover your previous deleted blocks, click the small garbage can located in the lower left hand side. This will take you to all of your previously deleted blocks, where they will be stored for seven days before they are permanently deleted.