After added synchronized lyrics to both "a.mp3" and "b.mp3", I restart window media player 11 and use mouse to drag both "a.mp3" and "b.mp3" from folder to the "Now Playing" list pane,
then click "Play" button, windows media player 11 begin to play "a.mp3" and shows the "Caption Frame" for displaying the synchronized lyrics, it's no problem for "a.mp3" ,
when the "a.mp3" is finished and windows media player turn to play "b.mp3" automatically,
Now, the problem is coming, the "Caption Frame" is automatically closed therefore the synchronized lyrics for "b.mp3" can't be display, At this time, if use mouse to double click on "b.mp3" at "Now Playing" list pane, the "Caption Frame" shows again and the synchronized lyrics for "b.mp3" displaying correctly.
It seems that windows media player 11 displays the "Synchronized Lyrics" only when you double click on one music or if there is only one music at "Now Playing" list pane.
If the "Now Playing" list pane have two or more musics, only the first music can display the "Synchronized Lyrics" correctly, the second or later nerver displays itself's synchronized lyrics.
Is this a bug in windows media player 11
How to solve this problem

"Synchronized Lyrics" problem (Or may be bug) with Windows Media Player 11
BetsyT