rem: this.imageDiv = OpenLayers.Util.createAlphaImageDiv(); 
add: var id = OpenLayers.Util.createUniqueID("OL_Icon_"); this.imageDiv = OpenLayers.Util.createAlphaImageDiv(id); 
context:     initialize: function(url, size, offset, calculateOffset) {        this.url = url;        this.size = (size) ? size : new OpenLayers.Size(20,20);        this.offset = offset;        this.calculateOffset = (calculateOffset) ? calculateOffset                                 : function(size) {                                     return new OpenLayers.Pixel(-(size.w/2),                                                                 -(size.h/2));                                   };        this.imageDiv = OpenLayers.Util.createAlphaImageDiv();    },
meta: 1027	/local1/tlutelli/issta_data/temp/all_js/javascript/2007_temp/2007/1027/dcd550ff31b398c03ca39ba3b370461a95652527/Icon.js/clean/lib/OpenLayers/Icon.js