The usual way to obtain it is to use
SetCtrlAttribute (panel, control, ATTR_VISIBLE, 0);
to hide the message and
SetCtrlAttribute (panel, control, ATTR_VISIBLE, 1);
to show it.
Another way to do this is to create the text message and place elsewere on the panel formatting it as desired, next create a square flat button (located on toggle button's palette) and make him the same size and position of the text message, arranging the toggle on top of the message. Next set the TRUE color of the toggle to transparent and set the control as indicator.
To display the message simply use
SetCtrlVal (panel, togglecontrol, 1);
and to hide it use
SetCtrlVal (panel, togglecontrol, 0);
The advantage of this method is that on the panel the message area rem
ains visible (outlined) which can be aestetically good (it depends on your personal taste).
Hope this helps
Roberto