OFN_ENABLEINCLUDENOTIFY top-level constant
Causes the dialog box to send CDN_INCLUDEITEM notification messages to your OFNHookProc hook procedure when the user opens a folder. The dialog box sends a notification for each item in the newly opened folder. These messages enable you to control which items the dialog box displays in the folder's item list.
const OFN_ENABLEINCLUDENOTIFY = 0x00400000;