This happens when renaming the `matches` method in the (yet not pushed) ``JUnitTestClassesFinderTest`` class.

Here is the stack trace

java.lang.reflect.InvocationTargetException
	at org.eclipse.jface.operation.ModalContext.run(ModalContext.java:421)
	at org.eclipse.ltk.internal.ui.refactoring.RefactoringWizardDialog2.run(RefactoringWizardDialog2.java:331)
	at org.eclipse.ltk.ui.refactoring.RefactoringWizard.internalPerformFinish(RefactoringWizard.java:605)
	at org.eclipse.ltk.ui.refactoring.UserInputWizardPage.performFinish(UserInputWizardPage.java:153)
	at org.eclipse.ltk.ui.refactoring.RefactoringWizard.performFinish(RefactoringWizard.java:678)
	at org.eclipse.ltk.internal.ui.refactoring.RefactoringWizardDialog2.okPressed(RefactoringWizardDialog2.java:455)
	at org.eclipse.jface.dialogs.Dialog.buttonPressed(Dialog.java:472)
	at org.eclipse.jface.dialogs.Dialog$2.widgetSelected(Dialog.java:624)
	at org.eclipse.swt.widgets.TypedListener.handleEvent(TypedListener.java:240)
	at org.eclipse.swt.widgets.EventTable.sendEvent(EventTable.java:84)
	at org.eclipse.swt.widgets.Display.sendEvent(Display.java:4128)
	at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1457)
	at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1480)
	at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1465)
	at org.eclipse.swt.widgets.Widget.notifyListeners(Widget.java:1270)
	at org.eclipse.swt.widgets.Display.runDeferredEvents(Display.java:3974)
	at org.eclipse.swt.widgets.Display.readAndDispatch(Display.java:3613)
	at org.eclipse.jface.window.Window.runEventLoop(Window.java:825)
	at org.eclipse.jface.window.Window.open(Window.java:801)
	at org.eclipse.ltk.ui.refactoring.RefactoringWizardOpenOperation$1.run(RefactoringWizardOpenOperation.java:181)
	at org.eclipse.swt.custom.BusyIndicator.showWhile(BusyIndicator.java:70)
	at org.eclipse.ltk.ui.refactoring.RefactoringWizardOpenOperation.run(RefactoringWizardOpenOperation.java:193)
	at org.eclipse.ltk.ui.refactoring.RefactoringWizardOpenOperation.run(RefactoringWizardOpenOperation.java:116)
	at scala.tools.eclipse.refactoring.RefactoringAction$class.runRefactoring(RefactoringAction.scala:68)
	at scala.tools.eclipse.refactoring.rename.GlobalRenameAction.runRefactoring(GlobalRenameAction.scala:28)
	at scala.tools.eclipse.refactoring.RefactoringAction$class.run(RefactoringAction.scala:73)
	at scala.tools.eclipse.refactoring.rename.GlobalRenameAction.run(GlobalRenameAction.scala:28)
	at scala.tools.eclipse.refactoring.rename.RenameAction.run(RenameAction.scala:34)
	at org.eclipse.ui.internal.handlers.ActionDelegateHandlerProxy.execute(ActionDelegateHandlerProxy.java:289)
	at org.eclipse.core.commands.Command.executeWithChecks(Command.java:476)
	at org.eclipse.core.commands.ParameterizedCommand.executeWithChecks(ParameterizedCommand.java:508)
	at org.eclipse.ui.internal.handlers.HandlerService.executeCommand(HandlerService.java:169)
	at org.eclipse.ui.internal.keys.WorkbenchKeyboard.executeCommand(WorkbenchKeyboard.java:468)
	at org.eclipse.ui.internal.keys.WorkbenchKeyboard.press(WorkbenchKeyboard.java:786)
	at org.eclipse.ui.internal.keys.WorkbenchKeyboard.processKeyEvent(WorkbenchKeyboard.java:885)
	at org.eclipse.ui.internal.keys.WorkbenchKeyboard.filterKeySequenceBindings(WorkbenchKeyboard.java:567)
	at org.eclipse.ui.internal.keys.WorkbenchKeyboard.access$3(WorkbenchKeyboard.java:508)
	at org.eclipse.ui.internal.keys.WorkbenchKeyboard$KeyDownFilter.handleEvent(WorkbenchKeyboard.java:123)
	at org.eclipse.swt.widgets.EventTable.sendEvent(EventTable.java:84)
	at org.eclipse.swt.widgets.Display.filterEvent(Display.java:1069)
	at org.eclipse.swt.widgets.Display.sendEvent(Display.java:4127)
	at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1457)
	at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1480)
	at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1465)
	at org.eclipse.swt.widgets.Widget.sendKeyEvent(Widget.java:1494)
	at org.eclipse.swt.widgets.Widget.sendKeyEvent(Widget.java:1490)
	at org.eclipse.swt.widgets.Canvas.sendKeyEvent(Canvas.java:493)
	at org.eclipse.swt.widgets.Composite.keyDown(Composite.java:594)
	at org.eclipse.swt.widgets.Display.windowProc(Display.java:5473)
	at org.eclipse.swt.internal.cocoa.OS.objc_msgSendSuper(Native Method)
	at org.eclipse.swt.widgets.Widget.callSuper(Widget.java:220)
	at org.eclipse.swt.widgets.Widget.windowSendEvent(Widget.java:2095)
	at org.eclipse.swt.widgets.Shell.windowSendEvent(Shell.java:2253)
	at org.eclipse.swt.widgets.Display.windowProc(Display.java:5535)
	at org.eclipse.swt.internal.cocoa.OS.objc_msgSendSuper(Native Method)
	at org.eclipse.swt.widgets.Display.applicationSendEvent(Display.java:4989)
	at org.eclipse.swt.widgets.Display.applicationProc(Display.java:5138)
	at org.eclipse.swt.internal.cocoa.OS.objc_msgSend(Native Method)
	at org.eclipse.swt.internal.cocoa.NSApplication.sendEvent(NSApplication.java:128)
	at org.eclipse.swt.widgets.Display.readAndDispatch(Display.java:3610)
	at org.eclipse.ui.internal.Workbench.runEventLoop(Workbench.java:2701)
	at org.eclipse.ui.internal.Workbench.runUI(Workbench.java:2665)
	at org.eclipse.ui.internal.Workbench.access$4(Workbench.java:2499)
	at org.eclipse.ui.internal.Workbench$7.run(Workbench.java:679)
	at org.eclipse.core.databinding.observable.Realm.runWithDefault(Realm.java:332)
	at org.eclipse.ui.internal.Workbench.createAndRunWorkbench(Workbench.java:668)
	at org.eclipse.ui.PlatformUI.createAndRunWorkbench(PlatformUI.java:149)
	at org.eclipse.ui.internal.ide.application.IDEApplication.start(IDEApplication.java:123)
	at org.eclipse.equinox.internal.app.EclipseAppHandle.run(EclipseAppHandle.java:196)
	at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.runApplication(EclipseAppLauncher.java:110)
	at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.start(EclipseAppLauncher.java:79)
	at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:344)
	at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:179)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
	at java.lang.reflect.Method.invoke(Method.java:597)
	at org.eclipse.equinox.launcher.Main.invokeFramework(Main.java:622)
	at org.eclipse.equinox.launcher.Main.basicRun(Main.java:577)
	at org.eclipse.equinox.launcher.Main.run(Main.java:1410)
Caused by: java.lang.AssertionError: assertion failed: Race condition detected: You are running a presentation compiler method outside the PC thread.[phase: <no phase>] Please file a ticket with the current stack trace at https://www.assembla.com/spaces/scala-ide/support/tickets
	at scala.Predef$.assert(Predef.scala:179)
	at scala.tools.nsc.Global.assert(Global.scala:238)
	at scala.tools.nsc.interactive.Global.assertCorrectThread(Global.scala:450)
	at scala.reflect.internal.Symbols$Symbol.rawInfo(Symbols.scala:1287)
	at scala.reflect.internal.Symbols$Symbol.info(Symbols.scala:1228)
	at scala.reflect.internal.Types$TypeRef.thisInfo(Types.scala:2365)
	at scala.reflect.internal.Types$TypeRef.baseClasses(Types.scala:2370)
	at scala.reflect.internal.Types$class.computeBaseClasses$1(Types.scala:1713)
	at scala.reflect.internal.Types$$anonfun$defineBaseClassesOfCompoundType$1.apply(Types.scala:1725)
	at scala.reflect.internal.Types$$anonfun$defineBaseClassesOfCompoundType$1.apply(Types.scala:1725)
	at scala.reflect.internal.Types$CompoundType.memo(Types.scala:1605)
	at scala.reflect.internal.Types$class.defineBaseClassesOfCompoundType(Types.scala:1725)
	at scala.reflect.internal.SymbolTable.defineBaseClassesOfCompoundType(SymbolTable.scala:13)
	at scala.reflect.internal.Types$CompoundType.baseClasses(Types.scala:1582)
	at scala.reflect.internal.Types$TypeRef.baseClasses(Types.scala:2370)
	at scala.reflect.internal.Symbols$Symbol.ancestors(Symbols.scala:1797)
	at scala.tools.refactoring.analysis.Indexes$IndexLookup$$anonfun$completeClassHierarchy$1.apply(Indexes.scala:76)
	at scala.tools.refactoring.analysis.Indexes$IndexLookup$$anonfun$completeClassHierarchy$1.apply(Indexes.scala:76)
	at scala.collection.TraversableLike$$anonfun$filter$1.apply(TraversableLike.scala:264)
	at scala.collection.immutable.List.foreach(List.scala:309)
	at scala.collection.TraversableLike$class.filter(TraversableLike.scala:263)
	at scala.collection.AbstractTraversable.filter(Traversable.scala:105)
	at scala.tools.refactoring.analysis.Indexes$IndexLookup$class.completeClassHierarchy(Indexes.scala:76)
	at scala.tools.refactoring.analysis.GlobalIndexes$GlobalIndex$$anon$1.completeClassHierarchy(GlobalIndexes.scala:24)
	at scala.tools.refactoring.analysis.NameValidation$class.isNameAlreadyUsedInClassHierarchy$1(NameValidation.scala:65)
	at scala.tools.refactoring.analysis.NameValidation$class.doesNameCollide(NameValidation.scala:77)
	at scala.tools.eclipse.refactoring.rename.GlobalRenameAction$RenameScalaIdeRefactoring$$anonfun$2$$anon$1.doesNameCollide(GlobalRenameAction.scala:45)
	at scala.tools.eclipse.refactoring.rename.GlobalRenameAction$RenameScalaIdeRefactoring.checkFinalConditions(GlobalRenameAction.scala:94)
	at org.eclipse.ltk.core.refactoring.CheckConditionsOperation.run(CheckConditionsOperation.java:85)
	at org.eclipse.ltk.core.refactoring.CreateChangeOperation.run(CreateChangeOperation.java:121)
	at org.eclipse.ltk.core.refactoring.PerformChangeOperation.run(PerformChangeOperation.java:209)
	at org.eclipse.core.internal.resources.Workspace.run(Workspace.java:2344)
	at org.eclipse.ltk.internal.ui.refactoring.WorkbenchRunnableAdapter.run(WorkbenchRunnableAdapter.java:87)
	at org.eclipse.jface.operation.ModalContext$ModalContextThread.run(ModalContext.java:121)

Mirko, would you have time to have a look at it before the Helium release? If not, then please change the Milestone to Lithium.