Fixed the problem with extraneous <lg> tags, after confirming with Karin that all lines are consecutively numbered. Added more GUI extras to make life easier -- dialog boxes now remember their previous folders between sessions, and the ".xml" extension is forced when saving a file.

I also figured out the Look-and-feel issue; you have to set the look and feel before initComponents() creates all your components. I've now set it to use the look and feel of the platform, which seems to work; on Windows it looks like Windows, on Linux it uses GTK, and to test on Mac I joined the Apple Connection developer club and downloaded the last test build of their Java 1.6 machine (from September last year). This runs the app just fine.

Finally, I tried re-coding for backward compatibility with the 1.5 engine. One minor problem was the FileNameExtensionFilter class, which is new to 1.6; after coding around that successully using a class based on FileFilter, I hit a showstopper with the new GroupLayout manager, which the NetBeans IDE uses by default. That would take serious work to code around, so I gave up. We don't need this app to be very portable really.