Error while closing

[amilopowers]

What steps will reproduce the problem?

What is the expected result?

What happens instead?

Please provide any additional information below. Attach a screenshot if possible.

URL:http://josm.openstreetmap.de/svn/trunk
Repository:UUID: 0c6e7542-c601-0410-84e7-c038aed88b3b
Last:Changed Date: 2016-12-29 22:33:24 +0100 (Thu, 29 Dec 2016)
Build-Date:2016-12-30 02:35:18
Revision:11420
Relative:URL: ^/trunk

Identification: JOSM/1.5 (11420 de) Linux Fedora 25 (Workstation Edition)
Memory Usage: 618 MB / 910 MB (362 MB allocated, but free)
Java version: 1.8.0_111-b16, Oracle Corporation, OpenJDK 64-Bit Server VM
Screen: :0.0 1680x1050
Maximum Screen Size: 1680x1050
Java package: openjdk-8-jre:Das Paket openjdk-8-jre ist nicht installiert

Plugins:
+ apache-commons (32994)
+ buildings_tools (33004)
+ conflation (0.3.0)
+ ejml (32680)
+ geotools (33042)
+ jts (32699)
+ opendata (33088)
+ turnrestrictions (33088)
+ utilsplugin2 (33088)

Map paint styles:
- https://josm.openstreetmap.de/josmfile?page=Styles/Coloured_Streets&zip=1

Last errors/warnings:
- W: java.io.IOException: Attribution is not loaded yet
- W: java.io.IOException: Attribution is not loaded yet
- W: java.io.IOException: Attribution is not loaded yet
- W: java.io.IOException: Attribution is not loaded yet
- W: java.io.IOException: Attribution is not loaded yet
- W: java.io.IOException: Attribution is not loaded yet
- W: java.io.IOException: Attribution is not loaded yet
- W: java.io.IOException: Attribution is not loaded yet
- W: java.io.IOException: Attribution is not loaded yet
- E: Handled by bug report queue: java.lang.IllegalArgumentException: Listener Conflation (instance of org.openstreetmap.josm.plugins.conflation.ConflationToggleDialog) was not registered before or already removed.


=== REPORTED CRASH DATA ===
DialogsPanel#destroy:
 - dialog: Conflation
 - dialog-class: class org.openstreetmap.josm.plugins.conflation.ConflationToggleDialog

BugReportExceptionHandler#handleException:
No data collected.

Warning issued by: BugReportExceptionHandler#handleException

=== STACK TRACE ===
Thread: AWT-EventQueue-0 (17) of main
java.lang.IllegalArgumentException: Listener Conflation (instance of org.openstreetmap.josm.plugins.conflation.ConflationToggleDialog) was not registered before or already removed.
	at org.openstreetmap.josm.tools.ListenerList.failRemove(ListenerList.java:134)
	at org.openstreetmap.josm.tools.ListenerList$TracingListenerList.failRemove(ListenerList.java:211)
	at org.openstreetmap.josm.tools.ListenerList.removeListener(ListenerList.java:128)
	at org.openstreetmap.josm.tools.ListenerList$TracingListenerList.removeListener(ListenerList.java:195)
	at org.openstreetmap.josm.data.Preferences.removePreferenceChangeListener(Preferences.java:243)
	at org.openstreetmap.josm.gui.dialogs.ToggleDialog.destroy(ToggleDialog.java:460)
	at org.openstreetmap.josm.gui.dialogs.DialogsPanel.destroy(DialogsPanel.java:326)
	at org.openstreetmap.josm.gui.MapFrame.destroy(MapFrame.java:320)
	at org.openstreetmap.josm.gui.MainPanel.updateContent(MainPanel.java:58)
	at org.openstreetmap.josm.gui.MainPanel$1.afterLastLayerRemoved(MainPanel.java:160)
	at org.openstreetmap.josm.gui.layer.MainLayerManager.realRemoveSingleLayer(MainLayerManager.java:270)
	at org.openstreetmap.josm.gui.layer.LayerManager.realRemoveLayer(LayerManager.java:228)
	at org.openstreetmap.josm.gui.layer.LayerManager.lambda$removeLayer$1(LayerManager.java:214)
	at org.openstreetmap.josm.gui.util.GuiHelper.runInEDTAndWaitWithException(GuiHelper.java:138)
	at org.openstreetmap.josm.gui.layer.LayerManager.removeLayer(LayerManager.java:214)
	at org.openstreetmap.josm.gui.layer.LayerManager.realResetState(LayerManager.java:455)
	at org.openstreetmap.josm.gui.layer.MainLayerManager.realResetState(MainLayerManager.java:376)
	at org.openstreetmap.josm.gui.util.GuiHelper.runInEDTAndWaitWithException(GuiHelper.java:138)
	at org.openstreetmap.josm.gui.layer.LayerManager.resetState(LayerManager.java:449)
	at org.openstreetmap.josm.Main.shutdown(Main.java:879)
	at org.openstreetmap.josm.gui.MainApplication.shutdown(MainApplication.java:120)
	at org.openstreetmap.josm.Main.exitJosm(Main.java:858)
	at org.openstreetmap.josm.gui.MainFrame$ExitWindowAdapter.windowClosing(MainFrame.java:162)
	at java.awt.AWTEventMulticaster.windowClosing(AWTEventMulticaster.java:349)
	at java.awt.AWTEventMulticaster.windowClosing(AWTEventMulticaster.java:349)
	at java.awt.Window.processWindowEvent(Window.java:2054)
	at javax.swing.JFrame.processWindowEvent(JFrame.java:305)
	at java.awt.Window.processEvent(Window.java:2013)
	at java.awt.Component.dispatchEventImpl(Component.java:4889)
	at java.awt.Container.dispatchEventImpl(Container.java:2294)
	at java.awt.Window.dispatchEventImpl(Window.java:2746)
	at java.awt.Component.dispatchEvent(Component.java:4711)
	at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:758)
	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:76)
	at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:86)
	at java.awt.EventQueue$4.run(EventQueue.java:731)
	at java.awt.EventQueue$4.run(EventQueue.java:729)
	at java.security.AccessController.doPrivileged(Native Method)
	at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:76)
	at java.awt.EventQueue.dispatchEvent(EventQueue.java:728)
	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)

[Klumbumbus]

similar to #13182 and #14136

[Don-vip]

Closed as duplicate of #14136.