Ah ok, interesting. The one I remember is actually a similar y offset problem but in the opposite side (drawing into the now thicker border on top). That was in rio though. I must admit I mechanically copied the changes from plan9port where it seemed reasonable and then continued replacing where it looked right. So that code has kind of heuristic reasoning :) Cool I'll probably look first into trying some of the ideas mentioned once I'm in reach of my laptop again -------- Original Message -------- On Dec 22, 2021, 9:39 AM, < igor@9lab.org> wrote: Quoth Philip Silva : […] > - glitches: the borders aren't calculated correctly (3rd patch for rio and acme is very wip) […] By glitches, do you mean issues like the one here: • https://9lab.org/img/plan9/acid.png …where there is an issue in computing the column growth ⁽¹⁾ (I think) manifesting itself as an artefact that looks like a white line at the bottom of an acme column. On small res displays this isn't noticeable, however, on high-res screens it is annoying. I stopped half way through due to lack of time debugging this (still on my todo list), and was wondering if you observed the same glitch. ⁽¹⁾ … https://9lab.org/plan9/debugging-with-acid/