smartgwt 4.0 and 4.1 IE8 support

Is IE 8 (win xp) supported in smartgwt 4.0 and 4.1? After update from 3.x it doesn't load in IE8 (standard and compatible mode, with cleared cache). I also tried the smartgwt showcase from your websites. There is the same problem, the showcase shows only the loading dialog.

Thanks Pavel