Engine crashes clicking the down-arrow after clicking in the File System blank area (no file selected)

[SamDevelopsCode]

Tested versions

Reproducible in 4.3beta1 in an empty project.

System information

Linux Mint 21.3

Issue description

The engine will crash if you click inside the blank area inside the file system (without a file selected) and then click the down arrow once.

reproduction_vid.mp4

Here is a verbose log for anyone interested -

ERROR: FATAL: Index p_index = -1 is out of bounds (((Vector *)(this))->_cowdata.size() = 1).
at: operator[] (./core/templates/vector.h:52)

================================================================
handle_crash: Program crashed with signal 4
Engine version: Godot Engine v4.3.beta.custom_build (5833f59)
Dumping the backtrace. Please include this when reporting the bug to the project developer.
[1] /lib/x86_64-linux-gnu/libc.so.6(+0x42520) [0x7682ab842520] (??:0)
[2] VectorWriteProxyTreeItem::Cell::operator (/home/booch/Documents/GodotCompiled/godot/./core/templates/vector.h:52 (discriminator 7))
[3] Tree::select_single_item(TreeItem*, TreeItem*, int, TreeItem*, bool*, bool) (/home/booch/Documents/GodotCompiled/godot/scene/gui/tree.cpp:2674)
[4] Tree::_go_down() (/home/booch/Documents/GodotCompiled/godot/scene/gui/tree.cpp:3394)
[5] Tree::gui_input(Ref const&) (/home/booch/Documents/GodotCompiled/godot/scene/gui/tree.cpp:3503)
[6] Control::_call_gui_input(Ref const&) (/home/booch/Documents/GodotCompiled/godot/scene/gui/control.cpp:1828)
[7] Viewport::_gui_input_event(Ref) (/home/booch/Documents/GodotCompiled/godot/scene/main/viewport.cpp:2201)
[8] Viewport::push_input(Ref const&, bool) (/home/booch/Documents/GodotCompiled/godot/scene/main/viewport.cpp:3249)
[9] Window::_window_input(Ref const&) (/home/booch/Documents/GodotCompiled/godot/scene/main/window.cpp:1683)
[10] void call_with_variant_args_helper<Window, Ref const&, 0ul>(Window*, void (Window::)(Ref const&), Variant const**, Callable::CallError&, IndexSequence<0ul>) (/home/booch/Documents/GodotCompiled/godot/./core/variant/binder_common.h:304 (discriminator 4))
[11] void call_with_variant_args<Window, Ref const&>(Window, void (Window::*)(Ref const&), Variant const**, int, Callable::CallError&) (/home/booch/Documents/GodotCompiled/godot/./core/variant/binder_common.h:419)
[12] CallableCustomMethodPointer<Window, Ref const&>::call(Variant const**, int, Variant&, Callable::CallError&) const (/home/booch/Documents/GodotCompiled/godot/./core/object/callable_method_pointer.h:104)
[13] Callable::callp(Variant const**, int, Variant&, Callable::CallError&) const (/home/booch/Documents/GodotCompiled/godot/core/variant/callable.cpp:57)
[14] Variant Callable::call<Ref >(Ref) const (/home/booch/Documents/GodotCompiled/godot/./core/variant/variant.h:876)
[15] DisplayServerX11::_dispatch_input_event(Ref const&) (/home/booch/Documents/GodotCompiled/godot/platform/linuxbsd/x11/display_server_x11.cpp:4034)
[16] DisplayServerX11::_dispatch_input_events(Ref const&) (/home/booch/Documents/GodotCompiled/godot/platform/linuxbsd/x11/display_server_x11.cpp:4011)
[17] Input::_parse_input_event_impl(Ref const&, bool) (/home/booch/Documents/GodotCompiled/godot/core/input/input.cpp:774)
[18] Input::flush_buffered_events() (/home/booch/Documents/GodotCompiled/godot/core/input/input.cpp:1053)
[19] DisplayServerX11::process_events() (/home/booch/Documents/GodotCompiled/godot/platform/linuxbsd/x11/display_server_x11.cpp:5151)
[20] OS_LinuxBSD::run() (/home/booch/Documents/GodotCompiled/godot/platform/linuxbsd/os_linuxbsd.cpp:960)
[21] /home/booch/Documents/GodotCompiled/godot/bin/godot.linuxbsd.editor.dev.x86_64(main+0x190) [0x5af516b07439] (/home/booch/Documents/GodotCompiled/godot/platform/linuxbsd/godot_linuxbsd.cpp:85)
[22] /lib/x86_64-linux-gnu/libc.so.6(+0x29d90) [0x7682ab829d90] (??:0)
[23] /lib/x86_64-linux-gnu/libc.so.6(__libc_start_main+0x80) [0x7682ab829e40] (??:0)
[24] /home/booch/Documents/GodotCompiled/godot/bin/godot.linuxbsd.editor.dev.x86_64(_start+0x25) [0x5af516b071e5] (??:?)
-- END OF BACKTRACE --

Steps to reproduce

Load minimal project.
Click inside the File System blank space (no file selected).
Click the down arrow.

Minimal reproduction project (MRP)

newnew.zip

[SamDevelopsCode]

Seems a potential fix has been written. Closing issue.