I wouldn't recommend changing the order via a text editor, especially if you have something like adjustable preview and/or a profile attached.
The best and most appropriate way to do this is to use the Define new order option on the Channel order drop down that is located just above the script editing area. When you select this, you get a rudimentary dialog that allows you to reorder. While it's not the best functionality, it works. A tip that I learned on this dialog is that you can double click at any place in the order (you will see a bar line when selected) and then a Ctrl + Click will move the selected channel to that location. It is a lot faster than trying to drag and drop achannel from the bottom of the list to the top

trust me I know.
Once you have the order the way you like it, make sure you click the save the current channel order to the right of that drop down. give it a name.
You can create multiple channel orders. It's nice if you want to work with just a particle color or a particle feature of you display, etc.
Hope this makes sense and helps.