The MapInfo Line Style Editor (MILISTED V.2.0) works by modifying the file from which MapInfo reads its line style definitions. MILISTED can open any valid MapInfo line style definition file, modify it, and save it with any name, however, MapInfo only experiences the changes when it starts up and reads the mapinfow.pen file it finds in the same directory as mapinfow.exe. You can have multiple line style definition files, but the only one that matters to MapInfo is the one named mapinfow.pen in the same directory as mapinfow.exe.
Utility Requirements:
MapInfo Pro v9.5 or lower