Script to reproduce UnreachableBrowserException with FirefoxDriver

gistfile1.java

import org.junit.Before;
import org.junit.After;
import org.junit.Test;
import org.openqa.selenium.WebDriver;
import org.openqa.selenium.WebElement;
import org.openqa.selenium.By;
import org.openqa.selenium.firefox.FirefoxDriver;
import org.openqa.selenium.support.ui.WebDriverWait;
import org.openqa.selenium.support.ui.ExpectedCondition;

public class IframeTest
{
        private WebDriver driver;

        @Before
        public void setUp() throws Exception
        {
                driver = new FirefoxDriver();
        }

        @Test
        public void test() throws Exception
        {
                driver.get( "http://www.baur.de" );
                isElementPresent( By.xpath( "//iframe[@title='Newsletter']" ), 20 );
                driver.switchTo().frame( driver.findElement( By.xpath( "//iframe[@title='Newsletter']" )));
                isElementPresent( By.cssSelector("input[type=\"submit\"]"), 10 );
        }

        @After
        public void tearDown() throws Exception
        {
                driver.quit();
        }

        private WebElement isElementPresent(final By by, int timeout)
        {
                return ( new WebDriverWait( driver, timeout ))
                        .until( new ExpectedCondition<WebElement>() {
                                @Override
                                public WebElement apply( WebDriver d ) {
                                return d.findElement( by );
                }});
        }
}