Hello.

Of the four filter options which kind of applications should be shown in the icons-only task manager, not all are written to the config file as boolean (see https://invent.kde.org/plasma/plasma-desktop/-/blob/02726a1ca0189f71f46513078cbc82af9daa9425/applets/taskmanager/package/contents/config/main.xml). 

There `showOnlyMinimized` is defined as an integer whereas the default value suggests that this is not intended.

This technically works during normal use (the default value is still keeps this option deactivated), it is however surprising when directly writing to the configuration file and it does not seem intentional due to the default value.