[OpenLayers-Users] Polygon doesn't align with baselayer with IE8

[Jessica Lapointe]

Hi everyone,
I display some wfs features over a baselayer. It looks great in all
browsers but Internet Explorer, in which my country polygons are off
by a few pixels. (Here's a screenshot: http://i.imgur.com/zPvq9.png )
The error is more or less important depending on the zoom level, but
it's never perfectly aligned as it is in chrome, firefox & safari.

I use OpenLayers 2.11 and mapserver 6.0.1. I didn't try with other
versions of IE.
Below are my map and layers definitions.

I have no idea how to fix this, so any clue would be appreciated.
Thanks a lot,
Jessica Lapointe

var myextent = new OpenLayers.Bounds(-180, -90, 180, 90);
        var options = { minScale: 150000000,
                units: "degrees",
                restrictedExtent: myextent,
                numZoomLevels: 6,
                controls: [new OpenLayers.Control.Navigation(), new
OpenLayers.Control.ArgParser()]
        };
        map = new OpenLayers.Map('map',  options);

        //WMS Background world map layer
        var worldLayer = new OpenLayers.Layer.WMS("countries",
                host+"phac.map&service=WMS",
                {layers:
'countries,countrieslabels'},{'isBaseLayer':true, 'singleTile': false}
        );
        map.addLayer(worldLayer);
        worldLayer.events.on({
                "loadend":onWorldLoaded
        });
        //WFS feature layer
        //Colored countries
        countriesLayer = new OpenLayers.Layer.Vector("Countries", {
                styleMap: styleMapCountries,
                strategies: [new OpenLayers.Strategy.BBOX()],
                protocol: new OpenLayers.Protocol.WFS({
                    url:host+"phac.map&service=WFS",
                    featureType: "projectcountries",
                    featureNS:  "http://mapserver.gis.umn.edu/mapserver"
                }),
                visibility: true
        });
        countriesLayer.events.on({
                "loadend":onCountriesLoaded
        });