--- a/servo/ports/geckolib/glue.rs
+++ b/servo/ports/geckolib/glue.rs
@@ -263,18 +263,17 @@ pub extern "C" fn Servo_TraverseSubtree(
     debug!("Servo_TraverseSubtree: {:?} {:?}", element, restyle_behavior);
 
     let traversal_flags = match (root_behavior, restyle_behavior) {
         (Root::Normal, Restyle::Normal) |
         (Root::Normal, Restyle::ForNewlyBoundElement) |
         (Root::Normal, Restyle::ForThrottledAnimationFlush)
             => TraversalFlags::empty(),
         (Root::UnstyledChildrenOnly, Restyle::Normal) |
-        (Root::UnstyledChildrenOnly, Restyle::ForNewlyBoundElement) |
-        (Root::UnstyledChildrenOnly, Restyle::ForThrottledAnimationFlush)
+        (Root::UnstyledChildrenOnly, Restyle::ForNewlyBoundElement)
             => UNSTYLED_CHILDREN_ONLY,
         (Root::Normal, Restyle::ForCSSRuleChanges) => FOR_CSS_RULE_CHANGES,
         (Root::Normal, Restyle::ForReconstruct) => FOR_RECONSTRUCT,
         _ => panic!("invalid combination of TraversalRootBehavior and TraversalRestyleBehavior"),
     };
 
     let needs_animation_only_restyle = element.has_animation_only_dirty_descendants() ||
                                        element.has_animation_restyle_hints();