Arc selection sometimes requires arc center in left->right mode

Description

This is an odd one I noticed when playing with the design from #9352 (closed). When I import that design and try to drag select the upper-left arcs using the left->right selection mode, it only selects the arcs when I include the arc center in the selection box. I tried drawing a normal arc on the canvas, and it seems to let me select it using left->right without the arc center (although it seems to be a bit sporadic sometimes).

ArcSelection-2021-10-10_16.41.17

Steps to reproduce

1. Import the DXF from #9352 (closed).
2. Try to left->right select the upper left set of 2 arcs and 2 lines without including the arc center
3. Note that the selection only includes 2 items instead of 4
4. Try selecting left->right again but this time include the arc center
5. See that now the selection has 4 items

KiCad Version

Application: KiCad PCB Editor

Version: (5.99.0-12758-g4d89061d4c), debug build

Libraries:
	wxWidgets 3.0.5
	libcurl/7.71.1 OpenSSL/1.1.1l-fips zlib/1.2.11 brotli/1.0.9 libidn2/2.3.2 libpsl/0.21.1 (+libidn2/2.3.0) libssh/0.9.5/openssl/zlib nghttp2/1.43.0

Platform: Linux 5.14.9-100.fc33.x86_64 x86_64, 64 bit, Little endian, wxGTK, mate, x11

Build Info:
	Date: Oct 10 2021 16:27:50
	wxWidgets: 3.0.5 (wchar_t,wx containers,compatible with 2.8) GTK+ 3.24
	Boost: 1.73.0
	OCC: 7.5.0
	Curl: 7.71.1
	ngspice: 33
	Compiler: Clang 11.0.0 with C++ ABI 1002

Build settings:
	KICAD_USE_OCC=ON
	KICAD_SPICE=ON
	KICAD_STDLIB_DEBUG=OFF
	KICAD_STDLIB_LIGHT_DEBUG=ON
	KICAD_SANITIZE_ADDRESS=OFF
	KICAD_SANITIZE_THREADS=OFF