Sectors: Adding a special, then crashes.

[UnBeatWaterGH]

SLADE Version: 3.2.3
Operating System: Debian Linux

Issue Details:
Was trying to add a special to a sector (a small one with a tech pole), and it just kinda crashes, any method I try to add that special doesn't work. In this case, I tried to use the Properties popup.

Version: 3.2.3
Current action: mapw_item_properties
Operating System: Linux 5.10.0-23-amd64 x86_64
Graphics Vendor: NVIDIA Corporation
Graphics Hardware: NVIDIA GeForce GTX 1650/PCIe/SSE2
OpenGL Version: 4.6.0 NVIDIA 470.182.03

Stack Trace:
0: [unknown location] wxLogger::DoLogWithNum(long, wchar_t const*, ...)
1: [unknown location] [unknown:140138922672937]
2: [unknown location] [unknown:140138885198144]
3: [unknown location] slade::SectorSpecialPanel::selectedSpecial() const
4: [unknown location] slade::SectorPropsPanel::applyChanges()
5: [unknown location] slade::mapeditor::editObjectProperties(std::vector<slade::MapObject*, std::allocator<slade::MapObject*> >&)
6: [unknown location] slade::Edit2D::editObjectProperties()
7: [unknown location] slade::MapEditContext::handleAction(std::basic_string_view<char, std::char_traits<char> >)
8: [unknown location] slade::SActionHandler::doAction(std::basic_string_view<char, std::char_traits<char> >)
9: [unknown location] SLADEWxApp::onMenu(wxCommandEvent&)
10: [unknown location] wxEvtHandler::ProcessEventIfMatchesId(wxEventTableEntryBase const&, wxEvtHandler*, wxEvent&)
11: [unknown location] wxEvtHandler::SearchDynamicEventTable(wxEvent&)
12: [unknown location] wxEvtHandler::TryHereOnly(wxEvent&)
13: [unknown location] wxEvtHandler::ProcessEventLocally(wxEvent&)
14: [unknown location] wxEvtHandler::ProcessEvent(wxEvent&)
15: [unknown location] wxEvtHandler::SafelyProcessEvent(wxEvent&)
16: [unknown location] wxMenuBase::SendEvent(int, int)
17: [unknown location] wxMenu::SetTitle(wxString const&)
18: [unknown location] g_closure_invoke
19: [unknown location] [unknown:140138888479763]
20: [unknown location] g_signal_emit_valist
21: [unknown location] g_signal_emit
22: [unknown location] gtk_widget_activate
23: [unknown location] gtk_menu_shell_activate_item
24: [unknown location] [unknown:140138896209731]
25: [unknown location] [unknown:140138897836552]
26: [unknown location] [unknown:140138888405742]
27: [unknown location] g_signal_emit_valist
28: [unknown location] g_signal_emit
29: [unknown location] [unknown:140138897485076]
30: [unknown location] [unknown:140138896121360]
31: [unknown location] gtk_main_do_event
32: [unknown location] [unknown:140138892879749]
33: [unknown location] [unknown:140138893091554]
34: [unknown location] g_main_context_dispatch
35: [unknown location] [unknown:140138887418136]
36: [unknown location] g_main_context_iteration
37: [unknown location] gtk_main_iteration
38: [unknown location] wxWindow::DoPopupMenu(wxMenu*, int, int)
39: [unknown location] wxWindowBase::PopupMenu(wxMenu*, int, int)
40: [unknown location] slade::mapeditor::openContextMenu()
41: [unknown location] slade::mapeditor::Input::mouseUp(slade::mapeditor::Input::MouseButton)
42: [unknown location] slade::MapCanvas::onMouseUp(wxMouseEvent&)
43: [unknown location] wxEvtHandler::ProcessEventIfMatchesId(wxEventTableEntryBase const&, wxEvtHandler*, wxEvent&)
44: [unknown location] wxEvtHandler::SearchDynamicEventTable(wxEvent&)
45: [unknown location] wxEvtHandler::TryHereOnly(wxEvent&)
46: [unknown location] wxEvtHandler::ProcessEventLocally(wxEvent&)
47: [unknown location] wxEvtHandler::ProcessEvent(wxEvent&)
48: [unknown location] wxEvtHandler::SafelyProcessEvent(wxEvent&)
49: [unknown location] wxWindow::DoThaw()
50: [unknown location] [unknown:140138897836315]
51: [unknown location] g_closure_invoke
52: [unknown location] [unknown:140138888479763]
53: [unknown location] g_signal_emit_valist
54: [unknown location] g_signal_emit
55: [unknown location] [unknown:140138897485076]
56: [unknown location] [unknown:140138896121360]
57: [unknown location] gtk_main_do_event
58: [unknown location] [unknown:140138892879749]
59: [unknown location] [unknown:140138893091554]
60: [unknown location] g_main_context_dispatch
61: [unknown location] [unknown:140138887418136]
62: [unknown location] g_main_loop_run
63: [unknown location] gtk_main
64: [unknown location] wxGUIEventLoop::DoRun()
65: [unknown location] wxEventLoopBase::Run()
66: [unknown location] wxAppConsoleBase::OnRun()
67: [unknown location] wxEntry(int&, wchar_t**)
68: [unknown location] main
69: [unknown location] __libc_start_main
70: [unknown location] _start

Last Log Messages:
Setting up the OpenGL context
Initialising OpenGL...
OpenGL Version: 4.6
Max Texture Size: 32768x32768
Checking extensions...
Vertex Buffer Objects supported
Point Sprites supported
Framebuffer Objects supported
Opening map MAP01
Removed 4 detached vertices, 0 detached sides, 0 invalid sides and 0 detached sectors