--- a/gfx/layers/apz/util/APZCCallbackHelper.cpp
+++ b/gfx/layers/apz/util/APZCCallbackHelper.cpp
@@ -244,17 +244,17 @@ APZCCallbackHelper::UpdateRootFrame(Fram
     // to be returned by window.innerWidth/innerHeight (see bug 1187792).
 
     float presShellResolution = shell->GetResolution();
 
     // If the pres shell resolution has changed on the content side side
     // the time this repaint request was fired, consider this request out of date
     // and drop it; setting a zoom based on the out-of-date resolution can have
     // the effect of getting us stuck with the stale resolution.
-    if (presShellResolution != aMetrics.GetPresShellResolution()) {
+    if (!FuzzyEqualsMultiplicative(presShellResolution, aMetrics.GetPresShellResolution())) {
       return;
     }
 
     // The pres shell resolution is updated by the the async zoom since the
     // last paint.
     presShellResolution = aMetrics.GetPresShellResolution()
                         * aMetrics.GetAsyncZoom().scale;
     shell->SetResolutionAndScaleTo(presShellResolution);