Bug 507465

***
If you're not sure this is actually a bug, instead post about it at https://discuss.kde.org

If you're reporting a crash, attach a backtrace with debug symbols; see https://community.kde.org/Guidelines_and_HOWTOs/Debugging/How_to_create_useful_crash_reports

Please remove this comment after reading and before submitting - thanks!
***

SUMMARY

When editing the "Desktop And Wallpaper" settings, and you go to the "Filter" screen, there is the option to hide matching files and a file name pattern to use. The default is "*" (i.e. match all) whilst the default mode is "Show all" which disables the other options.

When set to "Show Matching" and keeping the pattern as the default, no icons appear, whilst when set to "Hide Matching" with the default pattern, no icons appear.

Indeed when trying other configurations like "hide matching" and a pattern of "*~" (to hide temporary files) does not hide _any_ files what-so-ever. I have also tried other combinations of patterns like ".*~", ".*~$", ".*\~$" and all have produced the same result.

STEPS TO REPRODUCE
1. Right-click the desktop and select "Desktop and Wallpaper" (or 
2. On the wallpaper tab, set "Layout:" to "Folder View" (if you already didn't have it)
3. On the location tab set "Show:" to "Desktop folder" and make sure you have a variety of files in ~/Desktop
4. Click apply. The files should appear on the desktop
5. Go to the "Filter" tab.
6. Change "Files:" to "Show matching" and "File name pattern:" to "*" and click apply.
7. Change "Files:" to "Hide matching" and "File name pattern:" to "*" and click apply.
8. Change "Files:" to "Show matching" and "File name pattern:" to ".*" and click apply.
9. Change "Files:" to "Hide matching" and "File name pattern:" to ".*" and click apply.

OBSERVED RESULT

At #6 All icons disappear
At #7 All icons are shown
At #8 All icons disappear
At #9 All icons are shown

EXPECTED RESULT

At #6 All icons are shown
At #7 All icons disappear
At #8 All icons are shown
At #9 All icons disappear

SOFTWARE/OS VERSIONS
Operating System: Manjaro Linux 
KDE Plasma Version: 6.3.6
KDE Frameworks Version: 6.16.0
Qt Version: 6.9.1

ADDITIONAL INFORMATION

Additionally there is a list where you can select specific types to show - in the bottom-left below that list are "select all/deselect all" buttons that do absolutely nothing when clicked.