CMFCToolBarMenuButton::SetRadio
Sets the toolbar menu button to display a radio button style icon when it is checked.
virtual void SetRadio();
Remarks
When the menu button is drawn while it is checked, it calls CMFCVisualManager::OnDrawMenuCheck to draw a checkmark icon. By default, OnDrawMenuCheck requests that the current visual manager draws a checkbox style checkmark on the menu button. After you call this method, the current visual manager instead draws a radio button style checkmark on the menu button. This change cannot be undone.
When you call this method and the menu button is currently being displayed, it will refresh.
Requirements
Header: afxtoolbarmenubutton.h