229315 2021-08-19 17:42:22 -0700 Top layer elements should not be affected by parent layout (e.g. display: table-column or CSS content property) 2022-02-18 13:04:24 -0800 1 1 1 Unclassified WebKit Layout and Rendering WebKit Nightly Build Unspecified Unspecified RESOLVED WONTFIX InRadar P2 Normal --- 84635 1 ntim webkit-unassigned bfulgham simon.fraser webkit-bug-importer zalan oldest_to_newest 1785649 0 ntim 2021-08-19 17:42:22 -0700 2 main items from https://fullscreen.spec.whatwg.org/#new-stacking-layer : * If its position property computes to fixed, its containing block is the viewport, and the initial containing block otherwise. webkit.org/b/84796 imported/w3c/web-platform-tests/html/semantics/interactive-elements/the-dialog-element/removed-element-is-removed-from-top-layer.html [ ImageOnlyFailure ] webkit.org/b/84796 imported/w3c/web-platform-tests/html/semantics/interactive-elements/the-dialog-element/top-layer-containing-block.html [ ImageOnlyFailure ] webkit.org/b/84796 imported/w3c/web-platform-tests/html/semantics/interactive-elements/the-dialog-element/top-layer-stacking.html [ ImageOnlyFailure ] Modal dialogs have position: fixed by default with UA styles hence why it's relevant to those tests, and looking at the results, it's mostly top/bottom/right/left position which look wrong, making me think this is mostly containing block related. * It is rendered as an atomic unit as if it were a sibling of its root. Ancestor elements with [...] cannot affect it. webkit.org/b/84796 imported/w3c/web-platform-tests/html/semantics/interactive-elements/the-dialog-element/modal-dialog-in-replaced-renderer.html [ ImageOnlyFailure ] webkit.org/b/84796 imported/w3c/web-platform-tests/html/semantics/interactive-elements/the-dialog-element/modal-dialog-in-table-column.html [ ImageOnlyFailure ] These tests use particular cases like content: url() or display: table-column on the ancestor and open a modal dialog inside. 1785989 1 webkit-bug-importer 2021-08-20 14:37:23 -0700 <rdar://problem/82186174> 1802844 2 ntim 2021-10-11 15:27:16 -0700 The containing block bits have been split out to bug 231292 1843592 3 ntim 2022-02-18 13:04:24 -0800 This is the expected behaviour, we should work to get the spec changed.