Contains information about an item in a header control
Global Const $tagHDITEM = "int Mask;int XY;ptr Text;hwnd hBMP;int TextMax;int Fmt;int Param;int Image;int Order;int Type;ptr pFilter;int State"
| Mask | Flags indicating which other structure members contain valid data or must be filled in |
| XY | Width or height of the item |
| Text | Address of Item string |
| hBMP | Handle to the item bitmap |
| TextMax | Length of the item string |
| Fmt | Flags that specify the item's format |
| Param | Application-defined item data |
| Image | 0-based index of an image within the image list |
| Order | Order in which the item appears within the header control, from left to right |
| Type | Type of filter specified by pFilter |
| pFilter | Address of an application-defined data item |
| State | Item state |