Events and meanings: 1 --> Start 3 --> An OLE object is received, probably self OLE object ? 5 --> Word, 4th param is position, 5th param is length 6 --> ??? 7 --> Sentence, 4th param is position, 5th param is length 8 --> ??? 2 --> End https://learn.microsoft.com/en-us/previous-versions/windows/desktop/ms723587(v=vs.85)