gimp

Non-destructive healing allows you to "heal" the pixels of an image using a separate, dedicated layer so that you can undo or modify your changes at a later point in time. In (Photoshop and) GIMP, this essentially works by performing the heal on an empty layer using the Sample Merged option which allows you to perform the heal as if all the layers were merged together. While this works fine with the clone function, it is broken for healing in GIMP (2.8) due to this bug :(