I'm in the process of building a case feature into my typeface, and I know that feature usually includes punctuation, brackets, @ sign etc. but what about normal letters? For example, most fonts I've looked at don't include sub [a b c] by [A B C] but when selecting all caps in a layout program, these changes are still made. However, some letters, such as eth and eszett (and very bizarrely, ydieresis, which leads me to believe it might be a bug in the layout program - in this case, illustrator CS5), are not changed to their upper case counterparts (eszett is not even changed to SS, as one might expect). So my question is, should these glyphs be put in the case feature (sub germandbls by uni1E9E; sub eth by Eth; etc.) and if these glyphs are included in the feature, shouldn't a, b, c etc. also be included to make it cleaner?