[OpenLayers-Users] weird zoom behavior mouse wheel vs double click

[Alessandro Ferrucci]

Hello,
I have the following very simple map initialization code for
OpenLayers with google maps:

  var map;
            var projectionWGS84 = new OpenLayers.Projection("EPSG:4326");
            var projectionMercator = new OpenLayers.Projection("EPSG:900913");
            // Avoid pink error tiles
            OpenLayers.IMAGE_RELOAD_ATTEMPTS = 3;
            OpenLayers.Util.onImageLoadErrorColor = "transparent";

            function init(){

                var options = {
                    projection: new OpenLayers.Projection("EPSG:900913"),
                    displayProjection: new OpenLayers.Projection("EPSG:4326"),
                    units: "m",
                    numZoomLevels: 20,
                    maxResolution: 156543.0339,
                    maxExtent: new OpenLayers.Bounds(-20037508,
-20037508,20037508, 20037508),
                    controls:[
                            new OpenLayers.Control.Navigation(),
                            new OpenLayers.Control.ArgParser(),
                            new OpenLayers.Control.Attribution(),
                            new OpenLayers.Control.PanZoomBar({
position: new OpenLayers.Pixel(2, 15) }),
                            new OpenLayers.Control.Navigation(),
                            new OpenLayers.Control.Scale($('scale')),
                            new OpenLayers.Control.LayerSwitcher(),
                            new OpenLayers.Control.MousePosition(),
                            new OpenLayers.Control.Permalink()
                        ]

            };

                map = new OpenLayers.Map('map',options);
                var googleStreetLayer = new
OpenLayers.Layer.Google("Google Street", {'sphericalMercator':true} );
                map.addLayers([googleStreetLayer]);
                map.addControl(new OpenLayers.Control.LayerSwitcher());
                map.addControl(new OpenLayers.Control.MousePosition());
                var USABounds=new
OpenLayers.Bounds(-124.731,24.956,-66.97,49.372);
                USABounds.transform(projectionWGS84,map.getProjectionObject());
              //  map.zoomToMaxExtent();
                map.zoomToExtent(USABounds);
            }

This works fine however, the zoom behavior is weird when I zoom in and
out using the mouse wheel.
When I double click on the map the map zooms in 1 tick mark fine,
however when I use the mouse wheel to zoom in and out, it zooms 2
ticks at a time.

Has anyone ever encountered this behavior?  Any hints as to why it
would work as such?

I am using the following OpenLayers

<script src="http://openlayers.org/api/OpenLayers.js"
type="text/javascript"></script>

Thank you,
Alessandro Ferrucci