I am using the taxonomy module (D7) to list Continents, Countries, and Cities. Continents is the 1st level, Countries is the second level, Cities is the third. Or, in other words, Countries and Cities are children to Continents.
That's quite a number of terms.
All has been going well for a while but it seems I have reached some kind of a limit. Indeed, I can save new terms on the root level but when I move them to be children (at the 3rd level) the update no longer saves. There is no error message and no confirmation that the new configuration was saved. Indeed, the new terms are back to the root level after that.
I have added "max_input_vars = 1500" to my php.ini file but it didn't help.
The server generates no error.
Any idea or suggestion on how to fix this?
Update: If I move a term from the root directory to become the child of another term, the (new) automatic URL is not written in the database. I have to delete some existing terms to be able to save new terms (by the same number.) This tells me there is an imposed limit somewhere.