Watching graph event log
During a graph's lifetime different events may happen inside it (like changing its state
when it reaches the end of media being played)
and the graph object
supports IMediaEvent interface for working with them. Host application may be notified of
new events by receiving WM_GRAPHEVENT message to its window. GraphEditPlus handles this message
and requests new events from the graph via IMediaEvent::GetEvent() method, putting all the events
to a log together with timestamps.
From graph's context menu (right click on empty space in graph window) you can invoke
this window for watching event log for the graph. It's updated once a second and shows
the events translated to text and the times when they happened.