Selenium WebDriver have random timeout on select2 loading

org.openqa.selenium.TimeoutException: Timed out after 5 seconds waiting for org.nuxeo.functionaltests.forms.Select2WidgetElement$2@18e88380
Build info: version: '2.34.0', revision: '11cd0ef93615408e0b6b3bfa28defe125906461a', time: '2013-08-06 11:43:14'
System info: os.name: 'Windows Server 2008 R2', os.arch: 'amd64', os.version: '6.1', java.version: '1.7.0_17'
Driver info: driver.version: unknown
	at org.openqa.selenium.support.ui.FluentWait.timeoutException(FluentWait.java:259)
	at org.openqa.selenium.support.ui.FluentWait.until(FluentWait.java:228)
	at org.nuxeo.functionaltests.forms.Select2WidgetElement.selectValue(Select2WidgetElement.java:129)
	at org.nuxeo.functionaltests.pages.admincenter.usermanagement.UserCreationFormPage.createUser(UserCreationFormPage.java:87)
	at org.nuxeo.functionaltests.ITDefaultWorkflowTest.createTestUser(ITDefaultWorkflowTest.java:60)
	at org.nuxeo.functionaltests.ITDefaultWorkflowTest.testDefaultWorkflow(ITDefaultWorkflowTest.java:82)
	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:601)
	at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:44)
	at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:15)
	at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:41)
	at org.nuxeo.runtime.test.runner.FeaturesRunner$InvokeMethod.evaluate(FeaturesRunner.java:342)
	at org.junit.rules.TestWatchman$1.evaluate(TestWatchman.java:48)
	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$2.evaluate(ParentRunner.java:184)
	at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:28)
	at org.junit.internal.runners.statements.RunAfters.evaluate(RunAfters.java:31)
	at org.junit.runners.ParentRunner.run(ParentRunner.java:236)
	at org.nuxeo.runtime.test.runner.FeaturesRunner.run(FeaturesRunner.java:289)
	at org.apache.maven.surefire.junit4.JUnit4TestSet.execute(JUnit4TestSet.java:35)
	at org.apache.maven.surefire.junit4.JUnit4Provider.executeTestSet(JUnit4Provider.java:115)
	at org.apache.maven.surefire.junit4.JUnit4Provider.invoke(JUnit4Provider.java:97)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:601)
	at org.apache.maven.surefire.booter.ProviderFactory$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)