2.3.7 Header Textboxes
The header textbox document contains all of the content in the textboxes whose anchors are in the Header Document. It begins at the CP immediately following the Textbox Document and is FibRgLw97.ccpHdrTxbx characters long.
The locations of individual textboxes within the header textbox document are specified by a PlcfHdrtxbxTxt whose location is specified by the fcPlcfHdrtxbxTxt member of the FibRgFcLcb97. The locations of the textbox anchors in the Header Document are specified by a plcfSpa whose location is specified by the fcPlcSpaHdr member of the FibRgFcLcb97.
Not all members of a plcfSpa specify the location of a textbox. The lid member of the FTXBXS structure specifies the relationship between shape anchors and textbox anchors.