You can't just activate the string part. The tracks you see are the ones defined in the style you selected. Not all parts are in every style. So if those are greyed out, it just means that particular style doesn't include a strings track (melody and soloist tracks in general are not included in styles, but can be).

If you want a RealTrack strings to play, what you can do is to right click on one of the Strings part on the mixer and from the popup menu, select "Select RealTracks" to assign the RT to that strings track.

If you want MIDI strings to play, then you can select "Select Custom MIDI Style for this Track" (which lets you essentially import in a strings track from a style that has one you want. You would have to audition a number of MIDI styles first to find an appropriate one, however.

John

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