Investigate the possibility of automatic the javax/swing/JFileChooser/HTMLFileName.java test. The test has to ensure the file pane respects the value of "html.disable" and doesn't render file names as HTML by default; the navigation combo box has to respect it too.

Automating the test for Metal Look-and-Feel could also require significant effort, yet an automated test is always better than a manual one because it will allow catching failures in a more timely manner.

The test may need customisation for each L&F which may make it unfeasible for all L&Fs.