230438 2021-09-17 18:29:03 -0700 WKWebview sticky element with overflow scroll/auto causes elements to disappear during overscroll 2021-09-30 05:05:35 -0700 1 1 1 Unclassified WebKit CSS Other Unspecified Unspecified NEW InRadar P2 Normal --- 1 pklada webkit-unassigned kevin_neal knneth+webkit mrobinson simon.fraser webkit-bug-importer oldest_to_newest 1794724 0 pklada 2021-09-17 18:29:03 -0700 This doesn't seem to happen in mobile safari, only reproducible in a WKWebView. If I have a sticky element which is either itself set to overflow:scroll/auto or has a child with the same overflow rules, any child of those elements disappears during overscroll. They seem to disappear at the same moment that their container would otherwise have scrolled out of view (but is still visible due to being sticky). Note this doesn't happen with position: fixed elements, only position: sticky. Here is a video of the behavior: https://share.getcloudapp.com/jku40OLl The markup is relatively simple. A sticky positioned element, inside a div with overflow set to "auto" and white-space to "nowrap" so that the container is forced to scroll. Note that if the content doesn't actually force a scroll the bug doesn't seem to occur. Thanks 1795129 1 simon.fraser 2021-09-20 09:59:56 -0700 Could you please attach an HTML file with the markup that reproduces this? Thanks. 1795240 2 438720 pklada 2021-09-20 13:31:20 -0700 Created attachment 438720 Example html which repros the issue 1795245 3 pklada 2021-09-20 13:35:40 -0700 Video of repro w/ attached markup https://share.getcloudapp.com/GGupbKPE 1795635 4 webkit-bug-importer 2021-09-21 10:28:27 -0700 <rdar://problem/83357927> 438720 2021-09-20 13:31:20 -0700 2021-09-20 13:31:20 -0700 Example html which repros the issue sticky-disappearing-element-bug.html text/html 438 pklada PCFET0NUWVBFIGh0bWw+CjxodG1sPgogIDxib2R5PgogICAgPGRpdiBzdHlsZT0iaGVpZ2h0OiAy MDAwcHgiPgogICAgICA8ZGl2IHN0eWxlPSJoZWlnaHQ6IDEwMDBweCI+PC9kaXY+CiAgICAgIDxk aXYKICAgICAgICBzdHlsZT0icG9zaXRpb246IHN0aWNreTsgYm90dG9tOiAwOyBiYWNrZ3JvdW5k LWNvbG9yOiByZWQ7IGNvbG9yOiB3aGl0ZSIKICAgICAgPgogICAgICAgIDxkaXYgc3R5bGU9Im92 ZXJmbG93OiBhdXRvOyB3aGl0ZS1zcGFjZTogbm93cmFwIj4KICAgICAgICAgIFNvbWUgcmVhbGx5 IHJlYWxseSBsb25nIHRleHQgdGhhdCBjYXVzZXMgYW4gb3ZlcmZsb3cgYW5kIHNvbWV0aGluZwog ICAgICAgICAgdGhhdCBtYXkgb3IgbWF5IG5vdCBkaXNhcHBlYXIKICAgICAgICA8L2Rpdj4KICAg ICAgPC9kaXY+CiAgICA8L2Rpdj4KICA8L2JvZHk+CjwvaHRtbD4K