When I install a language via gnome-language-selector, it will install the input method (maybe Mozc?). But the problem is that when I remove the language, it won’t remove the input method, even every depends of the input method is set to manual-installed. So I have to remove them manually.
Maybe gnome-language-selector doesn’t manage the depends correctly, because normally the input method and its depends will be set to auto-installed, so that they would be removed when I remove the language.
It’s a correct observation.
When you install a language, it uses /usr/share/language-selector/data/pkg_depends to pull the related language support, for instance some input method. But, needless to say, it only installs packages which were not already installed.
When removing a language, and if we would let it uninstall everything according to pkg_depends, it would uninstall too much. It wouldn’t know which packages are there also for other reasons besides their relationship with the removed language.
The behavior was last changed in language-selector 0.104 in response to bug #37707.