I’ve fixed it now, I went here and followed the instructions about clearing my browser cache: https://www.ads-software.com/support/topic/279132?replies=100
I did this for all browsers. This got the text editor to appear correctly, but I was instead getting a ‘function’ error across the top of every page on my dashboard. I googled it and found this topic: https://www.ads-software.com/support/topic/278585?replies=50
Look for the user MichaelH, their response is really helpful – I downloaded the file and overwrote my http.php file with the new one, and now the errors are gone. Hope it works for you too. ??