tor-browser

commit ebad30b3999db38ee5e2c9b535c5ed53e499331a
parent 66d347cb0dba02332c82178c920f97e6c59b99ab
Author: Timothy Nikkel <tnikkel@gmail.com>
Date:   Wed, 26 Nov 2025 13:55:43 +0000

Bug 1988032. Disable RDL if are there active CSS anchor pos. r=layout-reviewers,emilio

Anchored content can get assigned an ASR that is "far away" from it with no relation in the frame tree. So if something about the ASR changes we need to invalidate the anchored content but that is not straight forward, and not worth it until/unless we find it causing an issue.

Differential Revision: https://phabricator.services.mozilla.com/D273601

Diffstat:
M
layout/generic/nsIFrame.cpp
 | 
8
++++++++

1 file changed, 8 insertions(+), 0 deletions(-)
diff --git a/layout/generic/nsIFrame.cpp b/layout/generic/nsIFrame.cpp
@@ -4435,6 +4435,14 @@ void nsIFrame::BuildDisplayListForChild(nsDisplayListBuilder* aBuilder,
         !PresContext()->Document()->GetActiveViewTransition()) {
       scrollsWithAnchor =
           AnchorPositioningUtils::GetAnchorThatFrameScrollsWith(child);
+
+      if (scrollsWithAnchor && aBuilder->IsRetainingDisplayList()) {
+        if (aBuilder->IsPartialUpdate()) {
+          aBuilder->SetPartialBuildFailed(true);
+        } else {
+          aBuilder->SetDisablePartialUpdates(true);
+        }
+      }
     }
 
     const ActiveScrolledRoot* asr =