glutAttachMenu, glutDetachMenu — attaches/detaches a mouse button for the current window to the identifier of the current menu
glutAttachMenu attaches a mouse button for the current window to the identifier of the current menu; glutDetachMenu detaches an attached mouse button from the current window. By attaching a menu identifier to a button, the named menu will be popped up when the user presses the specified button. button should be one of GLUT_LEFT_BUTTON, GLUT_MIDDLE_BUTTON, and GLUT_RIGHT_BUTTON. Note that the menu is attached to the button by identifier, not by reference.