Gmail – How to Create a New Category

A listing of other users expressing (various degrees of) outrage over the same topic can be found here. As before, the accepted solution doesn't work.

However, one person found a temporary solution using Adblock Plus (here, first message on Jun 26 (of 2013, I assume)):

It's not a problem to do this at all: go to ABP filter preferences, then select "Custom Filters" tab, then "Element Hiding Rules", then click "Add Filter". Now add following eight filters:

mail.google.com##.J-N[title="Social"]
mail.google.com##.J-N[title="Promotions"]
mail.google.com##.J-N[title="Updates"]
mail.google.com##.J-N[title="Forums"]
mail.google.com##.J-LC[title="Social"]
mail.google.com##.J-LC[title="Promotions"]
mail.google.com##.J-LC[title="Updates"]
mail.google.com##.J-LC[title="Forums"]

This seems to work for me. It's really regrettable, since the data is still there, the problem is still there, and this is really just a workaround that may break if Google changes the website's underlying code.

Still, in light of the fact that the "correct" solution to the problem doesn't seem to fix anything, there's not much else I can do. This temporary solution is permanent for me, unless Google can fix the underlying problem.

It's not possible to prevent mails from being automatically assigned to a category. You can disable tabs though.