after some things you do in the editor, you can "save changes".
i can't remember what those things are......sorry.
but with most changes, you only need to hit "enter" (key) on the line you are editing after you edit it, so that the line is saved. then you just exit when you are done editing. (i always use the "close project" option before i exit)
in other words, if you edit a line make sure you "enter" it and don't just click off of it instead, because it will not save the line.
of course if you want to see if the changes "took" then you can exit, reopen, then check for saved lines.
did i explain that ok?
-the dude