Silverlight controls getting stuck loading on IE

We're seeing some crazy behavior using Silverlight 4 on IE, on some machines, in some configurations. Here's the scenario

1) Silverlight controls used in our own custom Sharepoint WebParts (loading using the tag)

2) 2 web-part-containing-Silverlight instances on a page. That means 2 object tags, both pointing to the same XAP file but loading different user controls from that XAP

On some pages (but not all), the Silverlight loading seems to get stuck. The Silverlight controls don't render, the object tags' onload handler isn't called, and Fiddler is showing that the XAP isn't even being downloaded. Some interaction with IE (sometimes it's hovering over the control, sometimes it's clicking on the control region) can kickstart the loading process again, and the xap will download, onload is fired, and the controls are rendered. If I let it sit for a long time (like 2-3 minutes), sometimes the loading will resume and finish (but not always).

Since it hasn't even downloaded the XAP yet, it's not something in our code - it just seems like the loading gets blocked for some reason.

This only happens on IE, not on Chrome or Firefox. We've seen it on IE8 and IE7. It doesn't happen on every page with 2 SL contr开发者_高级运维ols, so the page contents seems to matter. We've also seen the problem running the web parts on straight ASP.NET (outside of Sharepoint), though much less frequently.

I've tried debugging with WinDBG, and it looks like some threads are in the guts of coreclr, but there's no debug symbols so I can't deduce much.

I was using webpart for Silverlight app in SharePoint. But finally found that its not the issue with webpart. In my case I removed all webpart from the default page and finally found that SharePoint default page is not loading.. I was using IE 9.

Solution: At the end I found that it was an issue related to Active X control. So I gone to Advance tab of Internet Options and did reset/restore all settings. Then once i started browsing the default page of the SharePoint website. Then ActiveX run request pops up. I allowed the ActiveX from Microsoft Corporation. Now Sharepoint default page is loading properly..

This happened to me as well. I have multiple XAPs loaded in one page and IE (sometimes Safari) just don't do anything. Nothing gets loaded. By using the Javascript API, it waits till the document is ready before embedding the tags. This way IE can take its time processing JS, CSS, HTML, MetaTags, etc, and then silverlight loads when everything is processed.