I had added some widgets on the desktop in Kubuntu 18 – two instances of Folder View widget in fact. After some time, I have removed them, but they re-appear after startup.
Removing them again and again, setting startup with empty session – nothing helped.
I think this widget is buggy enough to be completely uninstalled.
But it comes by default, was not manually installed, and therefore is not accessible in the Plasma Add-On Installer.
How to remove such widgets that were installed with the system?
Removing or renaming the folder /usr/share/plasma/plasmoids/org.kde.plasma.folder removes the widgets but leaves me with no wallpaper and no mouse actions on the desktop, so that is not a solution.
Best Answer
As @danzel said, the preinstalled widgets (Folder View, Notepad etc) are part of the plasma desktop package and hence can't be removed. The only way you would be able to do that would be to manually build plasma-desktop and possibly libkiofilewidgets after making modifications and then getting it to install.
But the reappearing widget issue probably can be solved by removing the config file that stores the applets present in
~/.config/plasma-org.kde.plasma.desktop-appletsrc. You can either remove them completely by following these instructions (which will also cause you to lose all your settings)First back it up just in case:
then remove it
Log out and log back in and you should have the default desktop configuration restored
Or
You could manually edit the same file and remove all references to anything named 'folder'