This message must be sent to the frame window whenever an application adds or removes one of the frame controls identified by the FCF_* flags. It must also be sent if the application adds or removes a submenu of the menu bar of the frame window.

The frame control window procedure first sends the message on to the FID_CLIENT window. The FID_CLIENT window might either reformat the frame window and set rc to TRUE, in which case the frame control window procedure takes no further action, or it might set rc to FALSE, in which case the frame control window procedure performs the reformatting.

If flCreateFlags contains FCF_SIZEBORDER, reformatting the frame window includes invalidating the area occupied by the size border.

The frame control window procedure sets rc to TRUE.