Force IE to render properly when using AJAX and Update Panel and tabs

Question

I have a ASP.NET form with a tab control with six tabs. When I load the page afresh in IE, the border appears and then two seconds later the tab control appears. The tabs are defined in individual ascx forms. This problem only occurs in IE, for Chrome and Firefox, the page appears all at once.

When I look at the source, there are 164 ScriptResource.axd requests which all add up. I've tried setting the CombineScripts of the ToolkitScriptmanager to True but that doesn't work. There's an updatepanel on three of the controls.

One of the combos has 1222 items. If I exclude the list, it goes down from 2 seconds to 1 second. Its still not good enough.

I am using IE10 on Win8.0.

How can I force the page to appear all at once?

Answer 1

It would turn out the website was set up so that it rendered for older browsers. We updated the x-ua-compatible metatag in global.asax and it works fine now.