The Google Gmail API filter by Label doesn't seem to work properly in case CATEGORY_PROMOTIONS.
When I used the query string -label:INBOX, the results did not list messages labeled INBOX. It is right.
BUT, I wanted to NOT list messages labeled CATEGORY_PROMOTIONS so I used the query string -label:CATEGORY_PROMOTIONS. BUT, the results are STILL listed messages labeled CATEGORY_PROMOTIONS.
Any experience with this? Is this a bug of Google Gmail API?