Debugging a bug that only affected left-handed users

Category: Engineering post
Status: discussion
Sources: blog post, HN discussion
Summary: A write-up traces a user-reported bug that turned out to reproduce only for left-handed users, walking through how an input assumption produced a defect correlated with handedness. It is a short debugging narrative.
Why it matters: It is a compact reminder that user-behavior assumptions baked into input handling produce defects that standard test matrices miss.