I am working on a screen in clicking a button runs the RadRichTextBox.Print() method, using either Html or HtmlPreview as parameters depending on which button you pressed. If I double click a button, there is a chance that I will get an "Eval failed" error. When I close the popup that displays the document, the error doesn't occur. Is there any way to check if that window is closed? If so, I could disable the functionality until the window is closed.