The FMEVENT_LOAD message is sent to an extension DLL when File Manager is loading the DLL.
FMEVENT_LOAD lpfmsld = (LPFMS_LOAD) lParam; /* address of struct. with delta */
An extension DLL must return TRUE to continue loading the DLL. If the DLL returns FALSE, File Manager calls the FreeLibrary function and ends any communication with the extension DLL.
An application should fill the dwSize, szMenuName, and hMenu members in the FMS_LOAD structure. It should also save the value of the wMenuDelta member and use it to identify menu items when modifying the menu.