If a user saves a decoration that has a plugin but no theme we currently
delete the entry saving just the plugin/library.
This is an issue as on load we call:
const QString plugin = config.readEntry("library", s_defaultPlugin); const QString theme = config.readEntry("theme", s_defaultTheme);
That would give us a non-default library with the default theme name,
which would be invalid.
If compiled with Breeze s_defaultTheme is blank so this ends up being
effectively the same thing. In the normal case it will neither break
nor fix anything.