Created attachment 156139 [details]
Display and Monitor systemsettings crash

SUMMARY
When trying to open various submenus in systemsettings, many menus will cause the systemsettings application to crash with a segfault.

Attached is a crash report from opening the Display and Monitor menu.

STEPS TO REPRODUCE
1. Open systemsettings
2. Select a submenu that causes it to crash (see list in ADDITIONAL INFORMATION)

OBSERVED RESULT
Systemsettings will immediately crash with a segfault.

EXPECTED RESULT
The submenu should open as expected.

SOFTWARE/OS VERSIONS
Linux/KDE Plasma: KDE neon 5.26
(available in About System)
KDE Plasma Version: 5.26.5
KDE Frameworks Version:  5.102.0
Qt Version: 5.15.8

ADDITIONAL INFORMATION

Submenus that cause a crash:
- Appearance
  - Plasma Style
  - Colors
  - Window Decorations
  - Fonts
  - Cursors
- Workspace Behavior
  - Virtual Desktops
- Startup and Shutdown
  - Background Services
- Search
  - Initial menu (can't explore further)
- Users
- Applications
  - Default Applications
- Firewall (if plasma-firewall is installed)
- Display and Monitor
  - Initial menu (can't explore further)
- Audio
- Software Update