Yeah. There was a time that you could use chrome://global/content/config.xul to get to the old about:config, but they removed that too. Don't know why they did that, only people who wanted the old behaviour would use it. Being able to sort by column is really useful, that's what I miss.

Edit: Didn't see your last line about chrome://global/content/config.xhtml , now I can get the old behaviour back. Thank you, thank you, thank you.