rem: botright.x - topleft.x, botright.y - topleft.y); 
add: Math.max(1, botright.x - topleft.x), Math.max(1, botright.y - topleft.y)); 
context:     drawMarker: function(marker) {        var bounds   = marker.bounds;        var topleft  = this.map.getLayerPxFromLonLat(                            new OpenLayers.LonLat(bounds.left,  bounds.top));        var botright = this.map.getLayerPxFromLonLat(                             new OpenLayers.LonLat(bounds.right, bounds.bottom));        if (botright == null || topleft == null) {            marker.display(false);        } else {            var sz = new OpenLayers.Size(                botright.x - topleft.x, botright.y - topleft.y);            var markerDiv = marker.draw(topleft, sz);            if (!marker.drawn) {                this.div.appendChild(markerDiv);                marker.drawn = true;            }        }    },
meta: 4411	/local1/tlutelli/issta_data/temp/all_js/javascript/2006_temp/2006/4411/21032bb71268caca0fbd2a1ffde4d9ed8bdb431d/Boxes.js/clean/lib/OpenLayers/Layer/Boxes.js