226739 2021-06-07 13:55:16 -0700 iFramed position:fixed element doesn't show in viewport after page regains focus 2026-02-23 18:33:08 -0800 1 1 1 Unclassified WebKit Compositing Safari 14 Mac (Intel) macOS 10.15 RESOLVED CONFIGURATION CHANGED InRadar P2 Normal --- 1 kdolan webkit-unassigned ahmad.saleem792 karlcow kdolan simon.fraser webkit-bug-importer oldest_to_newest 1767539 0 kdolan 2021-06-07 13:55:16 -0700 When an iFramed document contains a position:fixed element inside the scrollable body. The position fixed element moves along with the viewport fine when the page loads and has focus. But, tab away to another tab, then back to the page, and, in Safari, the position:fixed element is hidden at the top of the page. Not at the scrolled position. It's as if the container box is not the viewport anymore but the body. However, in Safari inspector, the position:fixed element is registering as existing in the viewport area. The position:fixed element's bounding box is in the fixed:position where the element should be visible. But, the position:fixed element is not visible there, its hidden at the top. The element only snaps into the viewport when the body is manually scrolled. Attempting to scroll the body with javascript does not show the position:fixed item in the viewport. This is only an issue in Safari. Firefox and Chrome show the item in its fixed position fine, with no problems, after the page gets focus again. Example: https://jsfiddle.net/khdolan/o1md489z In Safari, tab to another page and back to the rendered fiddle to see the issue. 1767541 1 simon.fraser 2021-06-07 14:04:33 -0700 Thanks for the report. 1767542 2 webkit-bug-importer 2021-06-07 14:04:46 -0700 <rdar://problem/78962618> 1769783 3 kdolan 2021-06-15 07:04:57 -0700 Possible related to the new Shadow DOM/Tree changes in Safari? However, this issue only happens when the iFramed page regains focus in Safari. 2183762 4 ahmad.saleem792 2026-02-21 10:18:12 -0800 I am not able to reproduce this on Safari 26.4 Beta - is it still reproducing for anyone? @Karl - any luck? 2184268 5 478451 karlcow 2026-02-23 18:32:58 -0800 Created attachment 478451 testcase It doesn't reproduce for me on macOS 15.7.3 with Safari Technology Preview 237, Chrome and Firefox latest versions. 478451 2026-02-23 18:32:58 -0800 2026-02-23 18:32:58 -0800 testcase testcase.html text/html 1044 karlcow PCFET0NUWVBFIGh0bWw+CjxodG1sIGxhbmc9ImVuIj4KPGhlYWQ+CiAgICA8bWV0YSBjaGFyc2V0 PSJVVEYtOCI+CiAgICA8bWV0YSBuYW1lPSJ2aWV3cG9ydCIgY29udGVudD0id2lkdGg9ZGV2aWNl LXdpZHRoLCBpbml0aWFsLXNjYWxlPTEuMCI+CiAgICA8dGl0bGU+QldPIDIyNjczOTwvdGl0bGU+ CiAgICA8c3R5bGU+CgojbXktbW9kYWwtY29udGFpbmVyIHsKICBtaW4taGVpZ2h0OiAyNDAwcHg7 CiAgYmFja2dyb3VuZC1pbWFnZTogbGluZWFyLWdyYWRpZW50KHJlZCAsIHllbGxvdyk7Cn0KCiNt eS1tb2RhbCB7CiAgcG9zaXRpb246IGZpeGVkOwogIGJvdHRvbTogMTNweDsKICBiYWNrZ3JvdW5k LWNvbG9yOiBibHVlOwogIGhlaWdodDogMTAwcHg7CiAgb3ZlcmZsb3c6IGF1dG87Cn0KCgogICAg PC9zdHlsZT4KPC9oZWFkPgo8Ym9keT4KPGRpdiBpZD0ibXktbW9kYWwtY29udGFpbmVyIj4KIDxk aXYgaWQ9Im15LW1vZGFsIj4KICAgVGhlIHBhcmFncmFwaCBpbiB0aGUgbW9kYWwgZGl2OgogICA8 cD4KICAgTG9yZW0gaXBzdW0gZG9sb3Igc2l0IGFtZXQsIGNvbnNlY3RldHVyIGFkaXBpc2Npbmcg ZWxpdCwgc2VkIGRvIGVpdXNtb2QgdGVtcG9yIGluY2lkaWR1bnQgdXQgbGFib3JlIGV0IGRvbG9y ZSBtYWduYSBhbGlxdWEuIFV0IGVuaW0gYWQgbWluaW0gdmVuaWFtLCBxdWlzIG5vc3RydWQgZXhl cmNpdGF0aW9uIHVsbGFtY28gbGFib3JpcyBuaXNpIHV0IGFsaXF1aXAgZXggZWEgY29tbW9kbyBj b25zZXF1YXQuIER1aXMgYXV0ZSBpcnVyZSBkb2xvciBpbiByZXByZWhlbmRlcml0IGluIHZvbHVw dGF0ZSB2ZWxpdCBlc3NlIGNpbGx1bSBkb2xvcmUgZXUgZnVnaWF0IG51bGxhIHBhcmlhdHVyLiBF eGNlcHRldXIgc2ludCBvY2NhZWNhdCBjdXBpZGF0YXQgbm9uIHByb2lkZW50LCBzdW50IGluIGN1 bHBhIHF1aSBvZmZpY2lhIGRlc2VydW50IG1vbGxpdCBhbmltIGlkIGVzdCBsYWJvcnVtLgogICA8 L3A+CiA8L2Rpdj4KPC9kaXY+CjxzY3JpcHQ+d2luZG93LnNjcm9sbCgwLCAxMDAwKTs8L3Njcmlw dD4KPC9ib2R5Pgo8L2h0bWw+