Before this ticket gets assigned to one of my colleagues, I will try to help.
Can you take a look at the browser console to see if there are any JavaScript errors when you click on that option and save it?
If you use Chrome, you can right-click on any blank space on the web page, select INSPECT, then select CONSOLE, and then re-do the process.
This might happen due to the current theme or one of the active plugins.
So one other thing you can try is this:
Please create a full website backup and let us know if the issue is still happening even when only the WPML plugins are active, and you are using a default WordPress theme.
Please try the following steps so that we can test for a compatibility-related issue:
- create a full website backup
- disable all plugins except WPML and its add-ons
- check if the issue is happening again
- if it's not, reactivate your plugins one by one, checking every time if the issue shows up again so that you can understand which plugin is causing that issue
If the issue happens even with the non-WPML plugins disabled:
- leave all the non-WPML plugins deactivated
- switch to a default theme like TwentySeventeen
- try to recreate the issue now
If you can, it would be best to do this in a staging (testing) environment.
Please let us know how that goes and if following these steps solved your issue or brought any change.
