Well , not really a complex tutorial this time but a funny tric to avoid desperation the pixel lock is the most wanted on the list but will arrive o 2.8 so i made this tutorial if you are inking comics and yo have ruined your sketch for some reason (ink in wrong layer) the idea comes from for his problem with comic inks. [link]
hope you like it. 4 pages of tutorial for a trick that will save you a lot of time redoing things!
Most really useful GIMP tutorials I've come across have been short and to the point. Usually following a very long tutorial I lose it or make a mistake along the way. This one was nice, although for lack of tablet I sketch on paper my usual solution was copies of each important layer invisible and stashed at the bottom. Your trick sounds neat. That from an amateurs point of view