diff --git a/widget/cocoa/nsCocoaWindow.mm b/widget/cocoa/nsCocoaWindow.mm
index d83c9050df73..9367ec253b7d 100644
--- a/widget/cocoa/nsCocoaWindow.mm
+++ b/widget/cocoa/nsCocoaWindow.mm
@@ -924,7 +924,7 @@ struct ShadowParams {
 
 // These numbers have been determined by looking at the results of
 // CGSGetWindowShadowAndRimParameters for native window types.
-static const ShadowParams kWindowShadowParameters[] = {
+static const ShadowParams kWindowShadowParametersPreYosemite[] = {
   { 0.0f, 0.0f, 0, 0, 0 },        // none
   { 8.0f, 0.5f, 0, 6, 1 },        // default
   { 10.0f, 0.44f, 0, 10, 512 },   // menu
@@ -932,6 +932,14 @@ static const ShadowParams kWindowShadowParameters[] = {
   { 4.0f, 0.6f, 0, 4, 512 }       // sheet
 };
 
+static const ShadowParams kWindowShadowParametersPostYosemite[] = {
+  { 0.0f, 0.0f, 0, 0, 0 },        // none
+  { 8.0f, 0.5f, 0, 6, 1 },        // default
+  { 9.882353f, 0.3f, 0, 4, 0 },   // menu
+  { 3.294118f, 0.2f, 0, 1, 0 },   // tooltip
+  { 9.882353f, 0.3f, 0, 4, 0 }    // sheet
+};
+
 // This method will adjust the window shadow style for popup windows after
 // they have been made visible. Before they're visible, their window number
 // might be -1, which is not useful.
@@ -946,7 +954,9 @@ nsCocoaWindow::AdjustWindowShadow()
       [mWindow canBecomeKeyWindow] || [mWindow windowNumber] == -1)
     return;
 
-  const ShadowParams& params = kWindowShadowParameters[mShadowStyle];
+  const ShadowParams& params = nsCocoaFeatures::OnYosemiteOrLater()
+    ? kWindowShadowParametersPostYosemite[mShadowStyle]
+    : kWindowShadowParametersPreYosemite[mShadowStyle];
   CGSConnection cid = _CGSDefaultConnection();
   CGSSetWindowShadowAndRimParameters(cid, [mWindow windowNumber],
                                      params.standardDeviation, params.density,