ConcurrentModificationException with instant refresh (sometimes)

[fac2003]

null
java.util.ConcurrentModificationException
at java.util.ArrayList$Itr.checkForComodification(ArrayList.java:901)
at java.util.ArrayList$Itr.next(ArrayList.java:851)
at jetbrains.mps.internal.collections.runtime.IterableUtils.visitAll(IterableUtils.java:16)
at jetbrains.mps.internal.collections.runtime.AbstractSequence.visitAll(AbstractSequence.java:80)
at org.campagnelab.instantrefresh.plugin.plugin.InstantRefresh_Tool.displayMessages(Unknown Source)
at org.campagnelab.instantrefresh.plugin.plugin.InstantRefresh_Tool$1$1.run(Unknown Source)
at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:311)
at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:756)
at java.awt.EventQueue.access$500(EventQueue.java:97)
at java.awt.EventQueue$3.run(EventQueue.java:709)
at java.awt.EventQueue$3.run(EventQueue.java:703)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:80)
at java.awt.EventQueue.dispatchEvent(EventQueue.java:726)
at com.intellij.ide.IdeEventQueue.defaultDispatchEvent(IdeEventQueue.java:863)
at com.intellij.ide.IdeEventQueue._dispatchEvent(IdeEventQueue.java:699)
at com.intellij.ide.IdeEventQueue.dispatchEvent(IdeEventQueue.java:385)
at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:201)
at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:116)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:105)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:101)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:93)
at java.awt.EventDispatchThread.run(EventDispatchThread.java:82)

[fac2003]

Fixed in master.