204559 2019-11-24 14:33:51 -0800 Dynamically inserting a slot element after the slot content does not work 2019-11-25 14:09:36 -0800 1 1 1 Unclassified WebKit New Bugs Safari 13 Mac macOS 10.15 RESOLVED DUPLICATE 199733 InRadar P2 Normal --- 1 jochen.kuehner webkit-unassigned rniwa webkit-bug-importer oldest_to_newest 1593289 0 jochen.kuehner 2019-11-24 14:33:51 -0800 Webcomponents dynamic added slots do not work see code on https://jsfiddle.net/t2z4kp3n/1/ Result is DivA DivB DivC but should be DivA DivB DivC DivD If you change order of 16-18 from let slot = document.createElement("slot"); slot.name = "d"; shadowRoot.appendChild(slot); to let slot = document.createElement("slot"); shadowRoot.appendChild(slot); slot.name = "d"; it works as expected. Also look in chrome, it works as it should 1593294 1 jochen.kuehner 2019-11-24 14:52:39 -0800 If you add the slot in the same cycle as you add the content but after it, the content will not be shown in the slot. If you assign the name to the slot after adding it, it would work 1593326 2 webkit-bug-importer 2019-11-24 22:34:30 -0800 <rdar://problem/57465685> 1593508 3 rniwa 2019-11-25 14:06:12 -0800 Doesn't reproduce in STP96. I'm pretty sure this is a duplicate of 199733. *** This bug has been marked as a duplicate of bug 199733 ***