Here's a long conversation on it from 2016: https://github.com/whatwg/html/issues/1929 https://github.com/whatwg/html/issues/1929 It does seem to have somethi

Here's a long conversation on it from 2016: https://github.com/whatwg/html/issues/1929 https://github.com/whatwg/html/issues/1929 It does seem to have something to do with interfering with automatic focus on the dialog when it pops up as a modal.