Is there a doc for ASG property: FixedDropDownMenu

I am looking at the newest version of the document: TMS TAdvStringGrid Developers Guide.pdf  I can not find any information of the event FixedDropDownClick which is copied below. I am also looking for information on the ASG property: FixedDropDownMenu. Is information on these items in a different help file?  

void __fastcall TForm1::AdvStringGrid1FixedDropDownClick(TObject *Sender, int ACol,
  int ARow, TPopupMenu *&AMenu, bool &KeepFixedCellHighlighted)

We have extended the doc with info about this that you can find on page 99/100