The behavior that you are describing is a browser behavior not related to our controls. Please note that IE will add the small "x" button to all input elements, when they are focused. What this button does is to clear the content of the input element, but once again, this is a browser related behavior.
I could suggest that you hide the clear button in IE also (since it is not available in any other browser). The following forum thread demonstrates how to achieve this:
Hope that helps.
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