Alternatively, sometimes DOM bugs in Internet Explorer may cause weird visual and mouse cursor behavior. We have had issues in IE with RadInput controls getting focused after an AJAX call that updates the control. Issues with such scenarios are very specific to the browser and usage behavior. Some can be worked around, but some cannot.
In any case, to be able to advise you further, we would need to reproduce the behavior you are observing. If you manage to isolate this issue in a test page or a standalone sample project, please send it to us (attached in a regular support ticket), so that we can investigate it. Alternatively, if you can send us a live URL where we can observe this behavior, this can also help us identify what may be causing this issue.
the Telerik team