Thanks for contacting us and for your questions. Currently, it is not possible to hide the whole default MDI menu since RadForm
control internally recalculates its non-client area in order to display it and this happens each time a MDI child form is maximized.
However, I can give you a possible workaround which simply hides the icon and the system buttons from the default MDI menu so that you can prevent your users from accessing them:
.FormElement.MdiControlStrip.MinimizeButton.Visibility = ElementVisibility.Collapsed;
.FormElement.MdiControlStrip.CloseButton.Visibility = ElementVisibility.Collapsed;
.FormElement.MdiControlStrip.MaximizeButton.Visibility = ElementVisibility.Collapsed;
.FormElement.MdiControlStrip.MaximizedMdiIcon.Visibility = ElementVisibility.Collapsed;
Please note that in this way the default MDI menu will continue appearing, but the buttons will not be accessible. I hope this is helpful. You can write back anytime you need further assistance.
All the best,
the Telerik team