| b10 | b16 | field | type | size | bitfield | comments |
| 0 | 0 | cTxbx | long | when not fReusable, counts the number of textboxes in this story chain | ||
| 0 | 0 | iNextReuse | long | when fReusable, the index of the next in the linked list of reusable FTXBXSs | ||
| 4 | 4 | cReusable | long | if fReusable, counts the number of reusable FTXBXSs follow this one in the linked list | ||
| 8 | 8 | fReusable | short | this FTXBXS is not currently in use | ||
| 10 | A | long | reserved | |||
| 14 | E | lid | long | Shape Identifier (see FSPA) for first Office Shape in textbox chain. | ||
| 18 | 12 | txidUndo | long |