Java hangs with GTK LaF on Ubuntu 13.04

Testsuite name: -
Test name(s): see attached file. i run it with
-Dswing.defaultlaf=com.sun.java.swing.plaf.gtk.GTKLookAndFeel
Product(s) tested: jdk
OS/architecture: Ubuntu 13.04 (both i586 & x64)

Error log file (if present): java hangs after JFrame is shown. JFrame is shown with transparent body for some reason. See screenshot attached

Reproducible: Always
Reproducible on machine: see comments for machines list


Is it a Regression: Not sure(Hangs on Ubuntu 13.04 and OK on Ubuntu 12.04)
[If Regression] Regression introduced in release/build:
Test result on the last GAed release for this train: Fail (8u20b26)
[if Fail] Test result on FCS: Fail (8b132)

Is it a platform specific issue: Yes/No
[If platform specific issue] Is it a new (previously unsupported) OS/browser/mode testing: Yes - Ubuntu 13.04