Silverlight controls getting stuck loading on IE -

we're seeing crazy behavior using silverlight 4 on ie, on machines, in configurations. here's scenario

1) silverlight controls used in our own custom sharepoint webparts (loading using tag)

2) 2 web-part-containing-silverlight instances on page. means 2 object tags, both pointing same xap file loading different user controls xap

on pages (but not all), silverlight loading seems stuck. silverlight controls don't render, object tags' onload handler isn't called, , fiddler showing xap isn't being downloaded. interaction ie (sometimes it's hovering on control, it's clicking on control region) can kickstart loading process again, , xap download, onload fired, , controls rendered. if let sit long time (like 2-3 minutes), loading resume , finish (but not always).

since hasn't downloaded xap yet, it's not in our code - seems loading gets blocked reason.

this happens on ie, not on chrome or firefox. we've seen on ie8 , ie7. doesn't happen on every page 2 sl controls, page contents seems matter. we've seen problem running web parts on straight asp.net (outside of sharepoint), though less frequently.

i've tried debugging windbg, , looks threads in guts of coreclr, there's no debug symbols can't deduce much.

i using webpart silverlight app in sharepoint. found not issue webpart. in case removed webpart default page , found sharepoint default page not loading.. using ie 9.

solution: @ end found issue related active x control. gone advance tab of internet options , did reset/restore settings. once started browsing default page of sharepoint website. activex run request pops up. allowed activex microsoft corporation. sharepoint default page loading properly..