Sometimes when executing the Seam validation, I get ConcurrentModificationException.

Steps to reproduce:

• create a large Seam project (as described in http://jira.jboss.com/jira/browse/JBIDE-1105#action_12394448 , for instance)
• open a few files in the VPE editor
• select the WebContent directory and choose Source>Format
• edit files during the Seam validation

Stack trace:

java.util.ConcurrentModificationException
at java.util.AbstractList$Itr.checkForComodification(AbstractList.java:372)
at java.util.AbstractList$Itr.next(AbstractList.java:343)
at org.jboss.tools.common.model.util.TypeInfoCollector.getProperties(TypeInfoCollector.java:843)
at org.jboss.tools.common.model.util.TypeInfoCollector.getPropertyPresentations(TypeInfoCollector.java:883)
at org.jboss.tools.seam.internal.core.el.SeamELCompletionEngine.resolveSeamELOperand(SeamELCompletionEngine.java:620)
at org.jboss.tools.seam.internal.core.el.SeamELCompletionEngine.resolveSeamELOperand(SeamELCompletionEngine.java:330)
at org.jboss.tools.seam.internal.core.validation.SeamELValidator.validateElOperand(SeamELValidator.java:293)
at org.jboss.tools.seam.internal.core.validation.SeamELValidator.validateEl(SeamELValidator.java:271)
at org.jboss.tools.seam.internal.core.validation.SeamELValidator.validateString(SeamELValidator.java:260)
at org.jboss.tools.seam.internal.core.validation.SeamELValidator.validateNodeContent(SeamELValidator.java:240)
at org.jboss.tools.seam.internal.core.validation.SeamELValidator.validateChildNodes(SeamELValidator.java:221)
at org.jboss.tools.seam.internal.core.validation.SeamELValidator.validateChildNodes(SeamELValidator.java:225)
at org.jboss.tools.seam.internal.core.validation.SeamELValidator.validateChildNodes(SeamELValidator.java:225)
at org.jboss.tools.seam.internal.core.validation.SeamELValidator.validateDom(SeamELValidator.java:194)
at org.jboss.tools.seam.internal.core.validation.SeamELValidator.validateFile(SeamELValidator.java:153)
at org.jboss.tools.seam.internal.core.validation.SeamELValidator.validate(SeamELValidator.java:106)
at org.jboss.tools.seam.internal.core.validation.SeamValidatorManager.validate(SeamValidatorManager.java:79)
at org.jboss.tools.seam.internal.core.validation.SeamValidatorManager.validateInJob(SeamValidatorManager.java:64)
at org.eclipse.wst.validation.internal.operations.ValidatorJob.run(ValidatorJob.java:75)
at org.eclipse.core.internal.jobs.Worker.run(Worker.java:55)