Ok, this one's just weird. The Close (X) button on MessageBox's TitleBar is not working. I click on it and nothing happens.
ds = Telerik.WinControls.RadMessageBox.Show(Me, "Are you sure?", "Clear form", MessageBoxButtons.YesNo, RadMessageIcon.Question, MessageBoxDefaultButton.Button1)
Edit: interestingly, it's the same with regular (native) MessageBox. As if the button is disabled. But why even show it then?