--- a/servo/components/style/servo/restyle_damage.rs
+++ b/servo/components/style/servo/restyle_damage.rs
@@ -59,17 +59,22 @@ impl HeapSizeOf for ServoRestyleDamage {
 
 impl ServoRestyleDamage {
     /// Compute the `StyleDifference` (including the appropriate restyle damage)
     /// for a given style change between `old` and `new`.
     pub fn compute_style_difference(old: &ServoComputedValues,
                                     new: &ServoComputedValues)
                                     -> StyleDifference {
         let damage = compute_damage(old, new);
-        let change = if damage.is_empty() { StyleChange::Unchanged } else { StyleChange::Changed };
+        let change =
+            if damage.is_empty() && old.get_custom_properties() == new.get_custom_properties() {
+                StyleChange::Unchanged
+            } else {
+                StyleChange::Changed
+            };
         StyleDifference::new(damage, change)
     }
 
     /// Returns a bitmask that represents a flow that needs to be rebuilt and
     /// reflowed.
     ///
     /// FIXME(bholley): Do we ever actually need this? Shouldn't
     /// RECONSTRUCT_FLOW imply everything else?