Manage ==> Categories not working in 2.1.2 (or 2.1.1

I am having the exact same problem.

I am using version 2.1. I am new to wordpress so I do not know if it is 2.1.0 or a newer version. I also cannot add a new category. I agree with Sorange that the “Add Category” button seems to do nothing.

A lot of the new wordpress functionality uses AJAX requests. So if you are blocking javascript or have adblockers or privacy blockers working, then these buttons may not actually work properly. Disable any such software and clear/reload your browser cache before trying again.

I checked and none of the things you mentioned are blocking anything or being blocked. But yes it does seem like it is the AJAX that is not working.

It’s also possible that some older themes or plugins are incompatible, and it’s entirely possible that they can interfere with this sort of thing. Look for any plugins/themes that use scriptaculous files and remove them. Failing that, disable plugins and see if you can figure out what is interfering.

I am using K2 for my theme. Does it seem likely that K2 would be incompatible?

Yes. Extremely likely for the case of K2 if you upgraded to 2.1 without upgrading the theme as well. Make sure you get the latest version of K2. It must be the 2.1 compatible version.

OK, I did have scriptaculous installed but wasn’t it using it for anything. I deleted it and things seem to work better but still not like they should. When I add a new tag it doesn’t automatically appear in the list. I have to hit reload on my browser to see it.

WordPress includes scriptaculous in it now, so if that was loading elsewhere, the function names would interfere and such.

Also, make sure you clear your browser cache after correcting the problem. Javascripts can be cached and still interfere even when they’re no longer on the server.

Woot! I finally got it to work. I deleted:
addEvent.js
moo.fx.js
moo.fx.pack.js
prototype-1.4.0.js
prototype.js
prototype.lite.js
quicktags.js
sweetTitles.js

and now it works like it’s supposed to. Thanks!

Oops, except on the page where you edit or enter a post, there is no longer an option to add a category. Was I not suppose to delete one of those?

I don’t know what any of those files are. Make sure you have all the files that are included in the default WordPress download.

For me this problem of categories not deleting was all because of browsers and javascript settings. I always post using Firefox because IE is too problem-laden. Even in Firefox I could only get categories (and pages) to delete and stay deleted when I first turned off Java and Javascripts and popup blocker in Firefox (under tools -> options). However, to be able to drag and drop widgets into sidebars I had to turn Java and Javascripts back on again. I didn’t take the time to find out which of these tools functions was really the most important – I just toggled them all off and then back on again.