It seems that your grid shows a single line only, therefore I see two options:
- Remove line breaks, therefore the fact that only the first line is displayed won't be any limitation anymore.
- Change the form to show more than a single line.
It seems that you're trying to implement the first scenario, but you can use a much simpler approach: strReplace() can replace line breaks with spaces, or anything you like. Also, I suggest you create a display method for this and use it (addLookupMethod()) in the lookup instead of Notes field. That's likely the easiest way possible.