To set the title to RadWindow's toolbar, we are using set_title(). This function however uses innerHTML (so you can additionally format the title when needed). In your case however, because the title is an HTML tag, the browser renders the textbox. Currently there is no way to override that, but I logged this issue in our PITS and we will improve the behavior of the control for one of the following updates. You can follow the PITS Issue by its ID: 2541
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