The mp2 parameter of this message points to a BOOKPAGEINFO data structure. The pBidiInfo field in this data structure points to the BOOKPAGEBIDIINFO structure.
The "fl" field of the BOOKPAGEINFO structure must have the BFA_BIDIINFO flag set to indicate that Bidi Attributes contained in the BOOKPAGEBIDIINFO structure are to be set for the Major Tab/Minor Tab/Status Line as indicated by the other flags set in this field.