The RadXmlHttpPanel has known compatibility issues with RadScriptManager and RadStyleSheetManager. Both managers combine all the requests (RadScriptManager combines the requests to the javascript assembly resource files and RadStyleSheetManager combines the ones to stylesheet resource files of all RadControls present on the page), into a single request.

Because the page does not go through its normal life cycle, after the RadControls have been updated by the RadXmlHttpPanel, the controls’ scripts and stylesheets need to be evaluated and applied, respectively. This, however cannot be done if the scripts (and the stylesheets) are combined into a single file - the RadXmlHttpPanel cannot find the right scripts and styles for the respective RadControl. That is why there might be client-script errors and the styles will not be applied correctly if the RadXmlHttpPanel is used together with the RadStyleSheetManager and the RadScriptManager.

There are 2 ways to solve this problem:

1. use the Microsoft AJAX ScriptManager control

   OR

2. set EnableScriptCombine="false" for RadScriptManager and EnableStyleSheetCombine="false" to RadStyleSheetManager.

Problem

When RadCompression is enabled and you are using .NET 4.0, event handlers might not be raised in a default document in IIS 7 or IIS 7.5 Integrated Mode, which could break the normal work of RadXmlHttpPanel.

Solution

This problem is caused by a breaking change in .NET 4.0 described here. To workaround it one can set preCondition="managedHandler" for the RadCompression module. You may also need to remove the runAllManagedModulesForAllRequests setting from your web.config if you have it (or set it to false).