Erstes Öffnen eines .joz files führt zu unerwarteter Ausnahme

[Basstoelpel]

What steps will reproduce the problem?

1. Save .joz files with local gpx layer but without data layer
2. Quit and restart josm
3. load file again

What is the expected result?

load the old data

What happens instead?

1st time after restart: "unerwartete Ausnahme"
2nd time: works as expected

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: 2016-08-20 01:28:07 +0200 (Sat, 20 Aug 2016)
Build-Date:2016-08-20 01:36:08
Revision:10859
Relative:URL: ^/trunk

Identification: JOSM/1.5 (10859 de) Windows 7 32-Bit
Memory Usage: 109 MB / 989 MB (58 MB allocated, but free)
Java version: 1.8.0_101-b13, Oracle Corporation, Java HotSpot(TM) Client VM

Plugins:
+ ColorPlugin (1414145445)
+ HouseNumberTaggingTool (32699)
+ Mapillary (32796)
+ PicLayer (32796)
+ apache-commons (32699)
+ apache-http (32699)
+ gson (32680)
+ imagery_offset_db (32796)
+ measurement (32732)
+ reverter (32796)
+ terracer (32699)
+ undelete (32699)
+ utilsplugin2 (32815)

Map paint styles:
- C:\Eigene Dateien\Styles_Power-style.mapcss
- https://josm.openstreetmap.de/josmfile?page=Styles/Maxspeed&zip=1


=== REPORTED CRASH DATA ===
BugReportExceptionHandler#handleException:
No data collected.

Warning issued by: BugReportExceptionHandler#handleException

=== STACK TRACE ===
Thread: AWT-EventQueue-0 (16) of main
java.lang.IllegalArgumentException: Listener PreferenceChangedListenerAdapter [listener=org.openstreetmap.josm.gui.layer.Layer$$Lambda$106/9699713@188701d] (instance of org.openstreetmap.josm.data.preferences.AbstractProperty$PreferenceChangedListenerAdapter) was not registered before or already removed.
	at org.openstreetmap.josm.tools.ListenerList.failRemove(ListenerList.java:129)
	at org.openstreetmap.josm.tools.ListenerList.removeListener(ListenerList.java:123)
	at org.openstreetmap.josm.data.Preferences.removeKeyPreferenceChangeListener(Preferences.java:282)
	at org.openstreetmap.josm.data.preferences.AbstractProperty.removeListenerImpl(AbstractProperty.java:262)
	at org.openstreetmap.josm.data.preferences.AbstractToStringProperty$ChildProperty.removeListenerImpl(AbstractToStringProperty.java:69)
	at org.openstreetmap.josm.data.preferences.AbstractProperty.removeListener(AbstractProperty.java:258)
	at org.openstreetmap.josm.gui.layer.Layer.removeColorPropertyListener(Layer.java:230)
	at org.openstreetmap.josm.gui.layer.Layer.setName(Layer.java:313)
	at org.openstreetmap.josm.gui.layer.GpxLayer.<init>(GpxLayer.java:94)
	at org.openstreetmap.josm.io.GpxImporter.loadLayers(GpxImporter.java:144)
	at org.openstreetmap.josm.io.GpxImporter.loadLayers(GpxImporter.java:174)
	at org.openstreetmap.josm.io.session.GpxTracksSessionImporter.load(GpxTracksSessionImporter.java:51)
	at org.openstreetmap.josm.io.session.SessionReader.parseJos(SessionReader.java:490)
	at org.openstreetmap.josm.io.session.SessionReader.loadSession(SessionReader.java:631)
	at org.openstreetmap.josm.io.session.SessionReader.loadSession(SessionReader.java:587)
	at org.openstreetmap.josm.actions.SessionLoadAction$Loader.realRun(SessionLoadAction.java:163)
	at org.openstreetmap.josm.gui.PleaseWaitRunnable.doRealRun(PleaseWaitRunnable.java:93)
	at org.openstreetmap.josm.gui.PleaseWaitRunnable.run(PleaseWaitRunnable.java:141)
	at java.util.concurrent.Executors$RunnableAdapter.call(Unknown Source)
	at java.util.concurrent.FutureTask.run(Unknown Source)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
	at java.lang.Thread.run(Unknown Source)