CloseAllShellExt cant close some shells

![screenshot from 2014-05-16 10 52 27](https://cloud.githubusercontent.com/assets/2078045/2995069/89dbe1e2-dcd7-11e3-9a24-cb8804e90830.png)


java.lang.AssertionError: The following shells remained open [Assignable Beans]
	at org.junit.Assert.fail(Assert.java:88)
	at org.jboss.reddeer.junit.extension.after.test.impl.CloseAllShellsExt.runAfterTest(CloseAllShellsExt.java:42)
	at org.jboss.reddeer.junit.internal.runner.RunAfters.evaluate(RunAfters.java:66)
	at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:271)
	at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:70)
	at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:50)
	at org.junit.runners.ParentRunner$3.run(ParentRunner.java:238)
	at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:63)
	at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:236)
	at org.junit.runners.ParentRunner.access$000(ParentRunner.java:53)
	at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:229)
	at org.jboss.reddeer.junit.internal.runner.FulfillRequirementsStatement.evaluate(FulfillRequirementsStatement.java:26)
	at org.jboss.reddeer.junit.internal.runner.RunAfters.evaluate(RunAfters.java:43)
	at org.junit.runners.ParentRunner.run(ParentRunner.java:309)
	at org.jboss.reddeer.junit.internal.runner.RequirementsRunner.run(RequirementsRunner.java:106)
	at org.junit.runners.Suite.runChild(Suite.java:127)
	at org.junit.runners.Suite.runChild(Suite.java:26)
	at org.junit.runners.ParentRunner$3.run(ParentRunner.java:238)
	at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:63)
	at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:236)
	at org.junit.runners.ParentRunner.access$000(ParentRunner.java:53)
	at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:229)
	at org.junit.runners.ParentRunner.run(ParentRunner.java:309)
	at org.junit.runners.Suite.runChild(Suite.java:127)
	at org.junit.runners.Suite.runChild(Suite.java:26)
	at org.junit.runners.ParentRunner$3.run(ParentRunner.java:238)
	at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:63)
	at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:236)
	at org.junit.runners.ParentRunner.access$000(ParentRunner.java:53)
	at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:229)
	at org.junit.runners.ParentRunner.run(ParentRunner.java:309)
	at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:50)
	at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)
	at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:459)
	at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:675)
	at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:382)
	at org.jboss.reddeer.eclipse.core.RemotePluginTestRunner.main(RemotePluginTestRunner.java:56)
	at org.jboss.reddeer.eclipse.core.UITestApplication.runTests(UITestApplication.java:115)
	at org.eclipse.e4.ui.internal.workbench.swt.E4Testable$1.run(E4Testable.java:72)
	at java.lang.Thread.run(Thread.java:744)