diff --git a/CanvasApp/Scales/RateScale.js b/CanvasApp/Scales/RateScale.js
index a532aea1f..5f67e3107 100644
--- a/CanvasApp/Scales/RateScale.js
+++ b/CanvasApp/Scales/RateScale.js
@@ -134,6 +134,42 @@ function newRateScale () {
   }
 
   function onMouseWheel (event) {
+    if (IS_MAC) {
+      let sensitivity
+      if (event.wheelDelta < 0) {
+        if (event.shiftKey === true) {
+          sensitivity = 20
+        } else {
+          sensitivity = 5
+        }
+        if (wheelDeltaDirection === -1) {
+          wheelDeltaCounter++
+          if (wheelDeltaCounter < sensitivity) {
+            return
+          } else {
+            wheelDeltaCounter = 0
+          }
+        } else {
+          wheelDeltaCounter = 0
+          wheelDeltaDirection = -1
+          return
+        }
+      } else {
+        if (wheelDeltaDirection === 1) {
+          wheelDeltaCounter++
+          if (wheelDeltaCounter < sensitivity) {
+            return
+          } else {
+            wheelDeltaCounter = 0
+          }
+        } else {
+          wheelDeltaCounter = 0
+          wheelDeltaDirection = 1
+          return
+        }
+      }
+    }
+
     if (event.shiftKey === true) {
       autoScaleButton.container.eventHandler.raiseEvent('onMouseWheel', event)
       return
diff --git a/CanvasApp/Scales/TimeFrameScale.js b/CanvasApp/Scales/TimeFrameScale.js
index 524bb7766..9c718e28e 100644
--- a/CanvasApp/Scales/TimeFrameScale.js
+++ b/CanvasApp/Scales/TimeFrameScale.js
@@ -289,6 +289,7 @@ function newTimeFrameScale () {
       }
     }
 
+    let delta = event.wheelDelta
     if (delta < 0) {
       timeFrameIndex--
       if (timeFrameIndex < 0) {