You can do this only by using GP script - or a Scriptlet, which i just wrote.
Save it in your GP-Favorites folder, then insert it from the favorites menu into your wiring view.
Then you can learn a widget to the “Show lyrics window” parameter.
But as Pianopaul said, you can not determine how the window should behave.
Scriptlet_OpenLyrics.gpfav (1.3 KB)
@dhj: I think, this functionality should be integrated in the System Actions plugin (not sure if this already had been proposed).