As the TODO comment suggests the old one is not very good here
While we're at it, I think the text could be improved too. "Edit Application", when read literally (as an average user is likely to do) implies that this actually alters the app itself, which is not accurate.
Since this action actually opens the properties window (which just happens to have a tab that allows you to edit the .desktop file), how about just, "Properties". Then we could use the standard document-properties icon.