Spitfire BBC Symphony Orchestra suddenly track went mute!

I’m working on a semi-orchestral piece in Cubase Pro 12 with several Instrument tracks using the excellent Spitfire BBC Symphony Orchestra samples. Suddenly one of the tracks went silent in the output mix.
The event now has a “white”, rather than a grey, background, but all the MIDI data and the volume data is still visible. The only place I can still hear the part is when clicking on the individual notes in the lower Event Editor window; but there’s no sound when playing the track through ‘Solo’ in that window - only when selecting individual notes with the mouse.
The final clue is that there is no information about Expression, Dynamics, Reverb, etc. under ‘Quick Controls’. It’s as if that track just stopped reading data from the Spitfire software - or something like that.
It is very strange because I didn’t even notice when it happened. I was editing the various parts and just noticed that, all of a sudden, the 1st Violins weren’t in the mix. Everything else was fine.
Any thoughts would be gratefully received. Thanks.

Hi,

Use the Mute tool to Unmute the MIDI Part(s).

Thank you, Martin. I didn’t know what or where that Mute tool was, but soon found it once you gave me the hint. Much appreciated, but it’s still a mystery how I muted it in the first place without knowing it!

Nonetheless, a basic error on my part.

Thanks again.

Hello.
I have another MIDI issue with BBC Symphony Orchestra in Cubase 12. When I Disable/Enable my Instruments tracks, my Mic Positions change. Disable/Enable turns on and off div Mic positions, and Cubase freeze for a long time.