I've looked into this issue a little more - the maximum single line length seems to be at least 1024 characters, however the maximum length is somewhat arbitrary, and there does not appear to be a method to control it. Today I was only able to enter text up to around 3000 characters before it started to wrap the text. The wrapped text is being saved/loaded correctly, so this does not seem to be an issue. I've made a change so that mIRC now takes account of wrapped lines when checking the script editor editbox.
