diff --git a/platforms/iOS/vm/OSX/sqSqueakOSXApplication+events.m b/platforms/iOS/vm/OSX/sqSqueakOSXApplication+events.m
index 37a0294102..c079e8a313 100644
--- a/platforms/iOS/vm/OSX/sqSqueakOSXApplication+events.m
+++ b/platforms/iOS/vm/OSX/sqSqueakOSXApplication+events.m
@@ -263,32 +263,74 @@ - (void) recordMouseEvent:(NSEvent *)theEvent fromView: (NSView <sqSqueakOSXView
 - (void) recordWheelEvent:(NSEvent *) theEvent fromView: (NSView <sqSqueakOSXView> *) aView{
 
 	[self recordMouseEvent: theEvent fromView: aView];
+	static float prevXDelta = 0;
+	static float prevYDelta = 0;
+	static int prevXTime = 0;
+	static int prevYTime = 0;
+#if (MAC_OS_X_VERSION_MAX_ALLOWED >= MAC_OS_X_VERSION_10_7)
+	CGFloat x = [theEvent scrollingDeltaX];
+	CGFloat y = [theEvent scrollingDeltaY];
+	/* Convert event units into scrolling units
+	   Assume that 1 event unit corresponds to a single wheel mouse notch
+	   A single notch evaluates to 120 scrolling units */
+	float xDelta = x * 120;
+	float yDelta = y * 120;
+	if ([theEvent respondsToSelector:@selector(hasPreciseScrollingDeltas)]) {
+		if ([theEvent hasPreciseScrollingDeltas]) {
+			/* Note: in case of precise scrolling x,y are given in points
+			   Assume that 120 scrolling units corresponds to 3 lines delta 
+			   that is 40 points for a 13.3 point line grid
+			   hence the factor 3 */
+			xDelta = x * 3;
+			yDelta = y * 3;
+		}
+	}
+#else
 	CGFloat x = [theEvent deltaX];
 	CGFloat y = [theEvent deltaY];
-
+	float xDelta = x * 120;
+	float yDelta = y * 120;
+#endif
+	/* accumulate enough delta before sending the event to the image */
+	int now = ioMSecs();
+	if( xDelta != 0 ) {
+		prevXDelta = ( now - prevXTime < 500) ? prevXDelta + xDelta : xDelta;
+		prevXTime = now;
+	}
+	if( yDelta != 0 ) {
+		prevYDelta = ( now - prevYTime < 500) ? prevYDelta + yDelta : yDelta;
+		prevYTime = now;
+	}
 	if (sendWheelEvents) {
+		float limit = 20;
+		if (-limit < prevXDelta && prevXDelta < limit && -limit < prevYDelta && prevYDelta < limit ) return;
 		sqMouseEvent evt;
 		memset(&evt,0,sizeof(evt));
 
 		evt.type = EventTypeMouseWheel;
 		evt.timeStamp = ioMSecs();
 
-		evt.x =  x * 32;
-		evt.y =  y * 32;
+		evt.x = prevXDelta;
+		evt.y = prevYDelta;
 
-		//printf("x:%f y:%f ex:%ld ey:%ld\n", x, y, evt.x, evt.y);
+		prevXDelta = 0;
+		prevYDelta = 0;
 
 		int buttonAndModifiers = [self mapMouseAndModifierStateToSqueakBits: theEvent];
-		evt.buttons = buttonAndModifiers >> 3;
+		evt.buttons = buttonAndModifiers & 7;
+		evt.modifiers = buttonAndModifiers >> 3;
 		evt.windowIndex =  aView.windowLogic.windowIndex;
 		[self pushEventToQueue:(sqInputEvent *) &evt];
 	}
 	else {
-		if (x != 0.0f) {
-			[self fakeMouseWheelKeyboardEventsKeyCode: (x < 0 ? 124 : 123) ascii: (x < 0 ? 29 : 28) windowIndex:   aView.windowLogic.windowIndex];
+		float limit = 120;
+		if (prevXDelta <= -limit || limit <= prevXDelta) {
+			[self fakeMouseWheelKeyboardEventsKeyCode: (prevXDelta < 0 ? 124 : 123) ascii: (prevXDelta < 0 ? 29 : 28) windowIndex: aView.windowLogic.windowIndex];
+			prevXDelta = 0;
 		}
-		if (y != 0.0f) {
-			[self fakeMouseWheelKeyboardEventsKeyCode: (y < 0 ? 125 : 126) ascii: (y < 0 ? 31 : 30) windowIndex:  aView.windowLogic.windowIndex];
+		if (prevYDelta <= -limit || limit <= prevYDelta) {
+			[self fakeMouseWheelKeyboardEventsKeyCode: (prevYDelta < 0 ? 125 : 126) ascii: (prevYDelta < 0 ? 31 : 30) windowIndex: aView.windowLogic.windowIndex];
+			prevYDelta = 0;
 		}
 	}
 }
diff --git a/platforms/unix/vm/sqUnixEvent.c b/platforms/unix/vm/sqUnixEvent.c
index f51a5d9c61..785ecdc64c 100644
--- a/platforms/unix/vm/sqUnixEvent.c
+++ b/platforms/unix/vm/sqUnixEvent.c
@@ -183,11 +183,14 @@ static void recordMouseEvent(void)
 
 static void recordMouseWheelEvent(int dx, int dy)
 {
+  int state= getButtonState();
   sqMouseEvent *evt= allocateMouseWheelEvent();
   evt->x= dx;
   evt->y= dy;
-  // VM reads fifth (4th 0-based) field for event's modifiers
-  evt->buttons= (getButtonState() >> 3);
+  evt->buttons= (state & 0x7);
+  evt->modifiers= (state >> 3);
+  evt->nrClicks=
+    evt->windowIndex= 0;
   signalInputEvent();
 #if DEBUG_MOUSE_EVENTS
   printf("EVENT (recordMouseWheelEvent): time: %d  mouse dx %d dy %d", evt->timeStamp, dx, dy);