diff --git a/html/semantics/interactive-elements/the-dialog-element/dialog-popover-closedby-complex.tentative.html b/html/semantics/interactive-elements/the-dialog-element/dialog-popover-closedby-complex.tentative.html
index aa45ecaad4ff8a..0d300595287a14 100644
--- a/html/semantics/interactive-elements/the-dialog-element/dialog-popover-closedby-complex.tentative.html
+++ b/html/semantics/interactive-elements/the-dialog-element/dialog-popover-closedby-complex.tentative.html
@@ -24,6 +24,7 @@
#popoverA { top: 150px; bottom: auto; padding:0; }
#dialogB { top: 200px; bottom: auto; padding:0; }
#popoverB { top: 250px; bottom: auto; padding:0; }
+ dialog { position: fixed; }