Gauge not lit

[arrow6x6]

I'm using FS Panel Studio for FSX.

Added an HSI to co-pilots panel in VC window 05; works good and lit at night. I put a copy of the same HSI on the VC Window01 (pilot's side) and it works fine but won't light at night! What have I done wrong? All the other gauges on the VC Window01 work and are lit at night, except this HSI.

Any help appreciated.