Created attachment 179757 [details]
Demo of the issue

SUMMARY
When you click the Global Theme button in Quick Settings, it shows just the left-most column and the Global Theme pane, missing out the Colors & Themes middle column. This is not the case for other shortcut buttons in Quick Settings.

STEPS TO REPRODUCE
1. Run System Settings
2. Maximise the window
3. Click Global Theme button within Quick Settings

OBSERVED RESULT
The window shows just the left-most category list and the Global Theme pane.

EXPECTED RESULT
The window shows the left-most category list, the Colors & Themes middle column, and the Global Theme pane.

SOFTWARE/OS VERSIONS
Operating System: openSUSE Tumbleweed 20250324
KDE Plasma Version: 6.3.3
KDE Frameworks Version: 6.12.0
Qt Version: 6.8.2
Kernel Version: 6.13.7-1-default (64-bit)
Graphics Platform: Wayland

ADDITIONAL INFORMATION
I think this is a problem because people reaching Global Theme from this route might not discover the other settings in Colors & Themes.

Note that this doesn't happen for other shortcut buttons in Quick Settings that may appear in the "Most used pages" section, such as Mouse and Audio CDs - these ones *do* show the middle column. Accessing Global Theme from the "Most used pages" section *does* demonstrate the issue (no middle column).