I don't know if this is something that slipped us from #1810386: Create workflow to setup multilingual for entity types, bundles and fields or its follow-up #1877048: Make Translation entity module JS follow newer core rules but there's a glitch I've noticed:
1. go to admin/config/regional/content-language
The idea in the steps below is that for each "thing" you want to enable translation or change language settings you
a. check the respective checkbox to show the table with the available options
b. make any config changes
c. save the form
d. uncheck the checkbox for the "thing" you just configured (to get it out of your way)
e. move on to the next item you need to configure and repeat steps a to e till done with configuration
So...
2. check the "Content" checkbox
3. enable translation for both the "Article" and the "Basic page" content types
4. change the setting for the "Default language" drop-down and check the "Show language selector on create and edit pages" checkbox
5. save
6. uncheck the "Content" checkbox
7. check the "Custom Block" checkbox
8. enable translation for the "Basic block"
9. change the setting for the "Default language" drop-down and check the "Show language selector on create and edit pages" checkbox
10. save
11. uncheck the "Custom Block" checkbox
12. check the "Taxonomy term" checkbox
13. enable translation for the "Tags" vocabulary
14. change the setting for the "Default language" drop-down and check the "Show language selector on create and edit pages" checkbox
15. save
...at this point you hit #1902758: Translation settings are available also for entity types not supporting translation and after reading what's wrong you:
16. uncheck the "TRANSLATABLE" checkbox from the "Tags" vocabulary
17. save (you still need to save changes because you took step 12 above)
You are shown the two success messages:
- Settings successfully updated.
- Successfully changed field translation setting....but:
- the "Custom Block" checkbox is checked (you unchecked that in step 11 above)
- the "Content" checkbox is checked (you unchecked it in step 6 above)
- the "TRANSLATABLE" checkboxes for the "Article" and the "Basic page" content types as well as for the "Basic block" are all unchecked??? WTF?!?
- the changes made in the "Default language" drop-down menus and the "Show language selector on create and edit pages" checkboxes (steps 4, 9 and 14 above ) are retained.
So, it seems that unchecking any previously checked checkbox from the "Custom language settings" set of checkboxes and saving the form also disables translatability but doesn't affect the language settings. These checkboxes at the top are meant only for showing/hiding the tables below. Right? They are not there to wipe any setting if unchecked. Right?