WM_QUERYBORDERSIZE - Remarks

The frame window responds to this message by returning the width and height of its border in the pSize parameter, as follows:

• SV_CX/CYSIZEBORDER if FCF_SIZEBORDER is specified
  
• SV_CX/CYDLGFRAME if FCF_DLGBORDER is specified
  
• SV_CX/CYBORDER if FS_BORDER is specified.