Crazy how often it backfires, too. I wasted 15 minutes a few weeks ago checking a user report that a PDF I hosted was missing exactly half its pages. Eventually, after walking it through my workflow step by step and it not breaking, I realized that it was simply the PDF viewer hiding the horizontal scrollbar which told you that it was a two-page layout. We had both fallen for it. Thanks, GNOME et al! (╯°□°)╯︵ ┻━┻

(This also illustrates the fallacy with the sibling comment blandly asserting that scrollbars should 'simply be hidden when not necessary'.)