SoapUI 3.6.1 does not come up after switching to 'native' LF

Hi

SoapUI does not come up on my ubuntu 10.04.1, java 1.6 after switching to native look and feel in the properties.
this is
java version "1.6.0_12"
Java(TM) SE Runtime Environment (build 1.6.0_12-b04)
Java HotSpot(TM) Server VM (build 11.2-b01, mixed mode)

on
Linux hostname 2.6.32-26-generic-pae #48-Ubuntu SMP Wed Nov 24 10:31:20 UTC 2010 i686 GNU/Linux


The message I get is this:
2010-12-02 14:04:16,316 [XpcMessageLoop] DEBUG com.jniwrapper.DefaultLibraryLoader - Finding library /usr/lib/libgthread-2.0.so.0.2400.1
2010-12-02 14:04:16,316 [XpcMessageLoop] DEBUG com.jniwrapper.DefaultLibraryLoader - Finding library in system library path...
14:04:16,689 INFO [DefaultSoapUICore] initialized soapui-settings from [/home/user/soapui-settings.xml]
14:04:17,573 INFO [WorkspaceImpl] Loading workspace from [/home/user/default-soapui-workspace.xml]
The program '<unknown>' received an X Window System error.
This probably reflects a bug in the program.
The error was 'BadIDChoice (invalid resource ID chosen for this connection)'.
(Details: serial 293 error_code 14 request_code 55 minor_code 0)
(Note to programmers: normally, X errors are reported asynchronously;
that is, you will receive the error a while after causing it.
To debug your program, run it with the --sync command line
option to change this behavior. You can then get a meaningful
backtrace from your debugger if you break on the gdk_x_error() function.)

regards,
Hans