gerbview XOR mode doesn't work as expected

Description / Beschreibung

gerbview: Der Exkclusiv-Oder-Modus funktionieren nicht. Es wird keine X-Oder/X-Or Funktion durchgeführt. / gerbview: Exclusive-or mode doesn't work. No XOR function is performed.

Steps to Reproduce / Reproduzieren

1. Öffne gerbview. / Open gerbview
2. Datei -> Gerber-datei(en) öffnen... / File -> Open Gerber plot file(s)... 3 Gerberdateien (entpackt) öffnen. / Open (unpacked) these Gerber files.
3. Ansicht -> Im XOR-Modus Anzeigen. / View -> View in XOR mode.
4. Bei Bedarf die Farben der Lagen ändern. / Change the colors of the layers if necessary.

KiCad Version

KiCad 8.99

Application: KiCad Gerber Viewer x86_64 on x86_64

Version: 8.99.0-233-g4a945172db, debug build

Libraries:
	wxWidgets 3.2.2
	FreeType 2.12.1
	HarfBuzz 6.0.0
	FontConfig 2.14.1
	libcurl/7.88.1 OpenSSL/3.0.11 zlib/1.2.13 brotli/1.0.9 zstd/1.5.4 libidn2/2.3.3 libpsl/0.21.2 (+libidn2/2.3.3) libssh2/1.10.0 nghttp2/1.52.0 librtmp/2.3 OpenLDAP/2.5.13

Platform: Debian GNU/Linux 12 (bookworm), 64 bit, Little endian, wxGTK, X11, LXQt, x11

Build Info:
	Date: Mar  4 2024 12:39:51
	wxWidgets: 3.2.2 (wchar_t,wx containers) GTK+ 3.24
	Boost: 1.74.0
	OCC: 7.6.3
	Curl: 7.88.1
	ngspice: 39
	Compiler: GCC 12.2.0 with C++ ABI 1017

Build settings:
	KICAD_STDLIB_DEBUG=OFF
	KICAD_STDLIB_LIGHT_DEBUG=OFF
	KICAD_SANITIZE_ADDRESS=OFF
	KICAD_SANITIZE_THREADS=OFF

Das gleiche Verhalten tritt auf mit KiCad 7.0 und KiCad 8.0 / Exactly the same happens in 7.0.