Hi Lotus,
I can indeed see that you have a lot of whitespace added to the top of your file.
I can not reproduce this issue with a clean install of WordPress, so I am wondering whether there may be a plugin conflicting with the AceIDE plugin installation.
Please note that if there is another plugin outputting extra whitespace, it will tamper with the download of the file contents into the browser. That is the issue in your case, lotusms.
If you go to the following URL, you will notice that extra whitespace is being output during an AJAX request, the request is not being handled because there is no action specified.
I would hazard a guess that this whitespace is coming from your theme’s functions.php file, as there may be some whitespace before the opening PHP tag. This will be added into files during editing, as they are downloaded with this extra whitespace.
I will have a look into some simple encoding so we may trash any output that is not file related, perhaps a simple base64 encoding of the file contents then trashing leading whitespace before decoding the file.
In the mean time, I hope this information helps you. If you would like, I can have a look at the install and see if I can spot any plugin conflicts.
Kind Regards,
Shane Thompson