I am not aware of other causes for this behavior than anchors, postbacks and/or setting focus (even default focus) in the RadWindow OR in the main form. Does this happen if you load a different page (e.g. an empty one) in the control? If not then something specific in this pace is causing the browser to attempt to scroll the page. The steps from this blog post
can help in determining what it is.
Setting the ShowContentDuringLoad to false moves the iframe that hosts the page outside of the visible viewport of the browser and puts it back in place when it loads. If this changes the scrolling behavior in the browser then the most likely cause for this is that something specific in the page behaves differently in this case.
the Telerik team
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