Thank you but where add add-post-category.php in the plugin content ? Or where can I found it ?   Best Regards, Noé

Hello, You have to add this hook: After adding this you’ll be able to add post category to question.

Hello Imran, This is just a notice, its not harmful and cannot cause a hangup. This error is coming from widget option this has nothing to do with user query. So, ignore this issue. Please install query monitor to check why site is hanging up. it must be due to while loop error.

Hello, Thanks for reporting. This is fixed and pushed to GitHub. But do not update in live site unless I mark it as stable.