Fix Element is no longer attached to the DOM error on Relation test

org.openqa.selenium.StaleElementReferenceException: Element is no longer attached to the DOM
Command duration or timeout: 28 milliseconds
For documentation on this error, please visit: http://seleniumhq.org/exceptions/stale_element_reference.html
Build info: version: '2.34.0', revision: '11cd0ef93615408e0b6b3bfa28defe125906461a', time: '2013-08-06 11:43:14'
System info: os.name: 'Linux', os.arch: 'amd64', os.version: '2.6.35.4-rscloud', java.version: '1.7.0_25'
Session ID: dfda8845-bb66-4f8f-af84-7422418b8e09
Driver info: org.openqa.selenium.firefox.FirefoxDriver
Capabilities [{platform=LINUX, databaseEnabled=true, cssSelectorsEnabled=true, javascriptEnabled=true, acceptSslCerts=true, handlesAlerts=true, browserName=firefox, browserConnectionEnabled=true, nativeEvents=false, webStorageEnabled=true, rotatable=false, locationContextEnabled=true, applicationCacheEnabled=true, takesScreenshot=true, version=22.0}]
	at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
	at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:57)
	at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
	at java.lang.reflect.Constructor.newInstance(Constructor.java:526)
	at org.openqa.selenium.remote.ErrorHandler.createThrowable(ErrorHandler.java:191)
	at org.openqa.selenium.remote.ErrorHandler.throwIfResponseFailed(ErrorHandler.java:145)
	at org.openqa.selenium.remote.RemoteWebDriver.execute(RemoteWebDriver.java:554)
	at org.openqa.selenium.remote.RemoteWebElement.execute(RemoteWebElement.java:268)
	at org.openqa.selenium.remote.RemoteWebElement.getAttribute(RemoteWebElement.java:122)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:606)
	at org.openqa.selenium.support.pagefactory.internal.LocatingElementHandler.invoke(LocatingElementHandler.java:41)
	at com.sun.proxy.$Proxy16.getAttribute(Unknown Source)
	at org.nuxeo.functionaltests.pages.tabs.RelationTabSubPage$2.apply(RelationTabSubPage.java:137)
	at org.nuxeo.functionaltests.pages.tabs.RelationTabSubPage$2.apply(RelationTabSubPage.java:135)
	at org.openqa.selenium.support.ui.FluentWait.until(FluentWait.java:208)
	at org.nuxeo.functionaltests.pages.tabs.RelationTabSubPage.setRelationWithDocument(RelationTabSubPage.java:152)
	at org.nuxeo.functionaltests.ITDocumentRelationTest.testSimpleRelationBetweenTwoDocuments(ITDocumentRelationTest.java:102)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:606)
	at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:44)
	at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:15)
	at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:41)
	at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:20)
	at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:28)
	at org.junit.internal.runners.statements.RunAfters.evaluate(RunAfters.java:31)
	at org.nuxeo.functionaltests.LogTestWatchman$1.evaluate(LogTestWatchman.java:101)
	at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:76)
	at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:50)
	at org.junit.runners.ParentRunner$3.run(ParentRunner.java:193)
	at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:52)
	at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:191)
	at org.junit.runners.ParentRunner.access$000(ParentRunner.java:42)
	at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:184)
	at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:28)
	at org.junit.internal.runners.statements.RunAfters.evaluate(RunAfters.java:31)
	at org.junit.runners.ParentRunner.run(ParentRunner.java:236)
	at org.apache.maven.surefire.junit4.JUnit4TestSet.execute(JUnit4TestSet.java:35)
	at org.apache.maven.surefire.junit4.JUnit4Provider.executeTestSet(JUnit4Provider.java:115)
	at org.apache.maven.surefire.junit4.JUnit4Provider.invoke(JUnit4Provider.java:97)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:606)
	at org.apache.maven.surefire.booter.ProviderFactory$ClassLoaderProxy.invoke(ProviderFactory.java:103)
	at com.sun.proxy.$Proxy0.invoke(Unknown Source)
	at org.apache.maven.surefire.booter.SurefireStarter.invokeProvider(SurefireStarter.java:150)
	at org.apache.maven.surefire.booter.SurefireStarter.runSuitesInProcess(SurefireStarter.java:91)
	at org.apache.maven.surefire.booter.ForkedBooter.main(ForkedBooter.java:69)
Caused by: org.openqa.selenium.remote.ErrorHandler$UnknownServerException: Element is no longer attached to the DOM
Build info: version: '2.34.0', revision: '11cd0ef93615408e0b6b3bfa28defe125906461a', time: '2013-08-06 11:43:14'
System info: os.name: 'Linux', os.arch: 'amd64', os.version: '2.6.35.4-rscloud', java.version: '1.7.0_25'
Driver info: driver.version: unknown
	at <anonymous class&gt;.fxdriver.cache.getElementAt(resource://fxdriver/modules/web_element_cache.js:7645)
	at <anonymous class&gt;.Utils.getElementAt(file:///tmp/anonymous2562977841071660788webdriver-profile/extensions/fxdriver@googlecode.com/components/command_processor.js:7231)
	at <anonymous class&gt;.WebElement.getElementAttribute(file:///tmp/anonymous2562977841071660788webdriver-profile/extensions/fxdriver@googlecode.com/components/command_processor.js:10311)
	at <anonymous class&gt;.DelayedCommand.prototype.executeInternal_/h(file:///tmp/anonymous2562977841071660788webdriver-profile/extensions/fxdriver@googlecode.com/components/command_processor.js:10816)
	at <anonymous class&gt;.DelayedCommand.prototype.executeInternal_(file:///tmp/anonymous2562977841071660788webdriver-profile/extensions/fxdriver@googlecode.com/components/command_processor.js:10821)
	at <anonymous class&gt;.DelayedCommand.prototype.execute/<(file:///tmp/anonymous2562977841071660788webdriver-profile/extensions/fxdriver@googlecode.com/components/command_processor.js:10763)