The demod scope can show you the FM multiplex. A broadcast FM station is not one signal but several stacked in frequency: the mono sum up to 15 kHz, a pilot tone at 19 kHz, the stereo difference channel on a suppressed 38 kHz carrier, RDS at 57 kHz, and sometimes a subsidiary subcarrier above that. The scope now has an MPX position that draws the whole of it over 0–100 kHz with each part named. It is the quickest way to see why a station is or is not in stereo, whether it is really sending RDS, and what the noise above 60 kHz on a weak signal actually is.
It appears only where it means something. Nothing else this receiver demodulates has a multiplex, so the MPX key exists while you are listening to wideband FM and in no other mode — not greyed out, simply not there. A scope left on MPX and reopened on an AM station shows the audio spectrum meanwhile and finds the multiplex again when you go back.
The rail row that stops decoders is now called what it does. It was "Decoders", which names what is inside it rather than what people open it for. It reads "Turn on and off plugins" now — the STOP key for a single decoder, and the one key that stops all of them, are both in there.
One thing fixed along the way. The labels were being placed against the nominal span of the spectrum while the picture under them ran one transform bin short of it. A fifth of a pixel, invisible on screen, and wrong by construction; the axis the labels use is now the one the bins actually cover.
Tested: 142 of 142 on Windows and on Linux. The multiplex view was measured against a synthesised composite — the receiver's own stereo decoder locked to its pilot, and the pilot, RDS and subcarrier tones each landed on the rule drawn for them.
SHA-256 of foxsdr-setup-0.99.12.exe:
c439cb9c449c0f617e25cd88de2a842a5279503e2254e117147b3d2d23f25fc2