Javascript error when submitting an existing taxonomy

[ThemeFuse.com]

When trying to add an existing taxonomy, a javascript error occurs: "Uncaught TypeError: Cannot read property 'supplemental' of undefined"

This is because the script will continue to try and add the taxonomy inside the select tag (inside the #addtag form), without checking whether the taxonomy is not null.

Solution: In tags.dev.js, on line 54, you need to check whether res.responses[1] is not null.

[solarissmoke]

I think it may be better to do a generic check for errors and if they exist, stop trying to process the response. The error message will have already been displayed by then.

[duck_]

In [20086]:

Bail from AJAX success callback if wp_ajax_add_tag() returns errors. Props solarissmoke. Fixes #20086.