After a long testing I am able to observe the issue only in Chrome by adding a RadFormDecorator to the provided sample markup. Could you check out if this RadControl causes the problem?
However, you can exclude the TextBox from the decorated controls, e.g.
"RadioButtons,CheckBoxes,Buttons,H4H5H6, Label,Select, Scrollbars, ValidationSummary, Fieldset, Textarea "
Additionally, this issue is already fixed, could you upgrade to the latest official version (Q3 2011 SP1) of Telerik RadControls amd see how it goes?
In case the problem persists without RadFormDecorator, please let me know in which browser you are able to observe the issue.
Looking forward to your reply.
the Telerik team
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