I ran the swingset on S9U2 CDE/dtwm with Tiger build 17, and a bunch of
output (for debugging?) was written to the console when I changed from either
the Java LAF or the Motif LAF to the GTK LAF.

echawkes@gradgrind:/net/jano/export/disk26/awt/echawkes( 1493 )% /java/jdk/bin/jdkx2 -r 1.5 swingset
cd /import/java/jdk1.5/solaris-sparc/demo/jfc/SwingSet2
/import/java/jdk1.5/solaris-sparc/bin/java -cp SwingSet2.jar:. SwingSet2
../gtk-2.0-key/gtkrc:6: Binding specification is unsupported, ignoring
../gtk-2.0-key/gtkrc:14: Binding specification is unsupported, ignoring
../gtk-2.0-key/gtkrc:16: Binding assignment is unsupported, ignoring
../gtk-2.0-key/gtkrc:17: Binding assignment is unsupported, ignoring
../gtk-2.0-key/gtkrc:18: Binding assignment is unsupported, ignoring
../gtk-2.0-key/gtkrc:6: Binding specification is unsupported, ignoring
../gtk-2.0-key/gtkrc:14: Binding specification is unsupported, ignoring
../gtk-2.0-key/gtkrc:16: Binding assignment is unsupported, ignoring
../gtk-2.0-key/gtkrc:17: Binding assignment is unsupported, ignoring
../gtk-2.0-key/gtkrc:18: Binding assignment is unsupported, ignoring
echawkes@gradgrind:/net/jano/export/disk26/awt/echawkes( 1494 )% /java/jdk/bin/jdkx2 -r 1.5 -showversion swingset
cd /import/java/jdk1.5/solaris-sparc/demo/jfc/SwingSet2
/import/java/jdk1.5/solaris-sparc/bin/java -showversion -cp SwingSet2.jar:. SwingSet2
java version "1.5.0-beta"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.5.0-beta-b17)
Java HotSpot(TM) Client VM (build 1.5.0-beta-b17, mixed mode)