The report from J.C. Stauttener was unusual. He had received the Dutch translation of TidBITS in email every week for years, but in the last few months, when he opened one, he wouldn’t be able to scroll in the issue. His workaround was to reply to the message, at which point he could scroll through the quoted text with no problem. The problem started in macOS 10.15 Catalina, he said, but it persisted through a clean install of macOS 11 Big Sur. Nor did the problem afflict any other messages—just TidBITS in Dutch.
I was, frankly, befuddled. None of my basic troubleshooting suggestions (testing in the preview pane versus a standalone window, trying a different user account or Mac, etc.) made any difference. While J.C. and I were going back and forth, our estimable Dutch translation team was investigating the problem as well. In short order, they figured it out.
We frequently embed YouTube videos and Google Forms-based surveys in articles on our Web site. It’s a superior user experience—rather than having to click a link and be sent off to YouTube or Google Forms, you can just watch the video or respond to the survey inline. However, email marketing company Mailchimp recommends against including embedded video and content that uses the IFRAME tag in email messages because most email clients either don’t support the necessary HTML tags or explicitly block them for security reasons (IFRAMEs often contain scripts that could potentially be malicious). As such, our custom WordPress-based system automatically strips embedded videos and IFRAMEs before sending an article in email or building an email issue. We always provide a backup text link for those receiving it in email.
I had failed to mention this technical quirk to our translators, who have always created their own processes for translating articles and assembling them into an issue. Since they start their translation from the Web version of each article, they were getting the embedded videos and IFRAMEs in their source material. The Japanese translation team had independently discovered the problem and stripped any IFRAMEs from their issues, but the Dutch team, unaware of the concern, left them in. We use IFRAMEs only infrequently, but because we were running surveys alongside Jeff Porten’s CES 2021 articles, they popped up in quite a few issues so far this year.
Therein lies the rub. Although Mailchimp says that Mail is the only major email client to support the HTML5 embedded media tags, it apparently cannot handle IFRAME content—or at least the IFRAMEs containing Google Forms that we were creating—or even fail gracefully. That’s a bug, and I’ve reported it. I don’t anticipate Apple devoting much attention to it, though, given how few people would accidentally include an IFRAME in email at this point in time.
Nevertheless, if you ever find yourself unable to scroll a message in Mail, the reason is likely due to an embedded IFRAME in the source. The workaround is to reply to the message and read the quoted text, and you will gain tech karma points for alerting the sender to the problem with a link to this article.