fill-column-indicator considered harmful
It's a rainy day here in Portland, so I've been puttering around with company-mode. I had the strangest bug: on triggering completion in a source code buffer, the tool-tip would appear on the extreme right-hand side of the window. I eventually tracked down the issue: fill-column-indicator. The bug can be understood here, but the TL;DR; is fill-column-indicator, as noted at the repo itself, is now obsolete– Emacs has shipped with display-fill-column-indicator-mode since version 27.