When net colours are on ("all"), hilighting non-coloured nets doesn't work

Description

In PCBNew, if I assign colours to a couple of nets, and set "net colours" to "all", then if I hilight another, non-coloured net, it doesn't hilight properly: tracks and zones don't hilight - only vias and PTH pads seem to hilight.

The nets which do have a colour assigned may be hilighted and this works fine.

I would have expected all nets to visually hilight as usual - for their zones and tracks to become a lighter colour when the net is hilighted.

image In the image, the GND net is supposedly hilighted - but only the vias and PTH pads are in fact drawn in a lighter colour - not the zones and tracks.

Steps to reproduce

  1. Open PCB new, creating a brand new kicad_pcb file.
  2. Import some nets and parts by clicking "Update PCB with changes made to schematic" - from an existing project.
  3. Assign a colour to one net.
  4. Ensure that "Net colours" is set to "All".
  5. Hilight a net that is not the one you just gave a colour, by ctrl+clicking some SMD pad with that net. It will not correctly visually hilight - its colour does not become lighter.

KiCad Version

Application: KiCad PCB Editor (64-bit)

Version: (6.0.0), release build

Libraries:
	wxWidgets 3.1.5
	libcurl/7.78.0-DEV Schannel zlib/1.2.11

Platform: Windows 10 (build 19042), 64-bit edition, 64 bit, Little endian, wxMSW

Build Info:
	Date: Dec 24 2021 19:17:02
	wxWidgets: 3.1.5 (wchar_t,wx containers)
	Boost: 1.76.0
	OCC: 7.5.0
	Curl: 7.78.0-DEV
	ngspice: 35
	Compiler: Visual C++ 1929 without C++ ABI

Build settings:
	KICAD_USE_OCC=ON
	KICAD_SPICE=ON