beanshell desktop freezes

[GoogleCodeExporter]

What steps will reproduce the problem?
1. start BeanShell Desktop with command 
  java -jar bsh-2.1b5.jar 

2. copy and paste example script into BeanShell Desktop Workspace

foo = "Foo";    
four = (2 + 2)*2/2;
print( foo + " = " + four );  // print() is a BeanShell command

// Do a loop
for (i=0; i<5; i++)
    print(i);   

// Pop up a frame with a button in it
button = new JButton( "My Button" );
frame = new JFrame( "My Frame" );
frame.getContentPane().add( button, "Center" );
frame.pack();
frame.setVisible(true);

3. press Enter

What is the expected output? What do you see instead?
BeanShell Desktop freezes

What version of the product are you using? On what operating system?
java "1.6.0_31"
bsh-2.1b5
Win7 x64

Original issue reported on code.google.com by michal.b...@gmail.com on 31 Oct 2012 at 4:29