The reason for this IE bug however is not in the RadWindow control so there isn't anything that we can do about it from our side. The actual reason for this behavior is the way IE treats content displayed in absolute positioned IFRAMEs (RadWindow is basically an IFRAME) and this bug is present since IE6. You can test this for yourself by putting a standard IFRAME in your parent page:
<iframe style="position:absolute; top:600px;" src="Popup.aspx" width="990px"; height="800px"></iframe>
and check the page in IE.
What I can suggest in your scenario is either to disable the autocomplete feature of the textbox or as an alternative - to use RadWindow as a control container
. In such case, the content is on the same page (not in an IFRAME) and the IE bug will not occur.
Another approach is to use the workaround provided by Mike.
the Telerik team
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