[Discuss-gnuradio] "LED" GUI widget?

[John Ackermann N8UR]

I'd like to have an indicator in the GUI (just a small circle is fine) 
light up when a Power Squelch block opens -- basically, an "in use" signal.

Is there a Qt widget that can do that, and is there a way to probe the 
Power Squelch for its state?  (I'd like to do this within GRC if possible.)

Thanks,
John