Dear list, I have the following sample: \startluacode fonts.handlers.otf.addfeature { name = "gpos_test", type = "single", data = { [ '¿' ] = 1000, [ '¡' ] = 1000, } } \stopluacode \definefontfeature[ktest][gpost_tes=yes] \starttext \startTEXpage[offset=1em] \feature[+][gpos_test] ¿? ¡! \stopTEXpage \stoptext This tries to move vertically the opening question and exclamation marks, so they are at the same height that its closing counterparts. I thought there may be a GPOS feature that could achieve this, but I must admit I have no idea about how to achive it. In my document, this should only work with the slanted feature. Could anyone tell me how could I move vertically single glyphs? Many thanks for your help, Pablo