Just to add an extra clarification; this works for the bank number, object number, ambiance numbers, music number, background number and of course, tileset. Basically anything that has to do with using a number to select something. Although egomassive sort of stated it; don't forget you can do something like Right clicking while holding shift to also go backwards by ten. And all the numbers loop from 255 to 0 (and back again). So in your case, if you're at 0 and want to go to 255, you're actually only a right click away. Good luck!