WM_QUEUESYNC
The WM_QUEUESYNC message is sent by a computer-based training (CBT) application to separate user-input messages from other messages sent through the journal playback hook (WH_JOURNALPLAYBACK).
This message has no parameters.
A CBT application should return zero if it processes this message.
Whenever a CBT application uses the journal playback hook, the first and last messages rendered are WM_QUEUESYNC. This allows the CBT application to intercept and examine user-initiated messages without doing so for events that it sends.