It also seems like Quick Edit doesn't work for the same reason. Seems to be a Prototype Error at the moment, and not just a Quick Reply thing.
Can you look at the error in Firefox with Firebug?? I don't get any errors to see it myself but Firebug sometimes gives better error messages than the Chrome developer tools.
I'll get one of my members to do it or I'll try later when I get to school. Firefox does not get the same errors on my computer, but it's a problem with Chrome.
I can't reproduce the issue with Firefox, I'll have to try other browsers at some other time...
Are there any javascript features on your forum that may only show to certain people?? As I can't think why some people would be getting errors when others wouldn't if there wasn't different/additional code being run somewhere for some people.
It's really weird, cause it's working for me right now.
Apart from that, no. I just have the MyBB defaults and a couple of js files from some plugins.
Just now I had a case here on mybb.com where after quick reply I couldn't use quick edit (button would go to full edit instead). But I can't remember if it was always like this and I can't reliably reproduce it either, so it might've been a fluke.
Here's Firebug on the Mac that gets the error.
Still having this problem with our forum regarding the Quick Reply. :s
Its not working in Firefox or Internet Explorer for us.
Better to make your own thread rather than post in somebody else's as it may be a different cause, and we'll need a URL and a test account for your forum too to be able to do anything.