BCGControlBar Pro for MFC
int CBCGPStaticLayout::AddGroupAnchor ( HWND  hWndGroup,
XMoveType  typeMove,
XSizeType  typeSize,
const CPoint &  percMove = CPoint(100, 100),
const CPoint &  percSize = CPoint(100, 100) 

Adds anchor for controls located inside specific group to layout manager.

hWndGroupA group window handler.
typeMoveDefines move direction.
typeSizeDefines resize method.
percMoveDefines (in percents) how far a child control is moved when a host is resized.
percSizeDefines (in percents) how child control is resized.
A number of controls located in the specified group.