Error closing data layer when activating JOSM and closing the data layer at the same time

[majkaz]

What steps will reproduce the problem?

1. switch to different program, part of JOSM stays visible on screen
2. switch back to JOSM by directly clicking data layer > close

What is the expected result?

1. JOSM gets activated
2. data layer is closed

Equally valid IMHO:

1. JOSM gets activated
2. nothing else happens

What happens instead?

Data layer is closed, but "Unexpected error" comes up.

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

URL:https://josm.openstreetmap.de/svn/trunk
Repository:UUID: 0c6e7542-c601-0410-84e7-c038aed88b3b
Last:Changed Date: 2018-12-03 01:53:41 +0100 (Mon, 03 Dec 2018)
Build-Date:2018-12-03 02:33:34
Revision:14500
Relative:URL: ^/trunk

Identification: JOSM/1.5 (14500 cs) Windows 10 64-Bit
OS Build number: Windows 10 Enterprise 1607 (14393)
Memory Usage: 248 MB / 989 MB (118 MB allocated, but free)
Java version: 1.8.0_121-b13, Oracle Corporation, Java HotSpot(TM) Client VM
Screen: \Display0 1920x1080
Maximum Screen Size: 1920x1080
VM arguments: [-Dhttp.proxyHost=xxxx, -Dhttp.proxyPort=8080, -Djosm.home=./, -Djosm.pref=./_IMPORT, -Djosm.userdata=./_IMPORT]

Plugins:
+ todo (30306)
+ utilsplugin2 (34506)

Last errors/warnings:
- E: java.util.concurrent.ExecutionException: [powershell, -Command, [Net.ServicePointManager]::SecurityProtocol = [Net.SecurityProtocolType]::Tls12;[System.Net.WebRequest]::Create('https://grca.nat.gov.tw').GetResponse()]
- W: No configuration settings found.  Using hardcoded default values for all pools.
- E: java.awt.datatransfer.UnsupportedFlavorException: Layer
- E: Handled by bug report queue: java.lang.NullPointerException


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

Warning issued by: BugReportExceptionHandler#handleException

=== STACK TRACE ===
Thread: AWT-EventQueue-0 (15) of main
java.lang.NullPointerException
	at org.openstreetmap.josm.gui.tagging.ac.AutoCompletionManager$1.layerRemoving(AutoCompletionManager.java:487)
	at org.openstreetmap.josm.gui.layer.LayerManager.fireLayerRemoving(LayerManager.java:475)
	at org.openstreetmap.josm.gui.layer.LayerManager.realRemoveSingleLayer(LayerManager.java:277)
	at org.openstreetmap.josm.gui.layer.MainLayerManager.realRemoveSingleLayer(MainLayerManager.java:305)
	at org.openstreetmap.josm.gui.layer.LayerManager.realRemoveLayer(LayerManager.java:265)
	at org.openstreetmap.josm.gui.layer.LayerManager.lambda$removeLayer$1(LayerManager.java:247)
	at org.openstreetmap.josm.gui.util.GuiHelper.runInEDTAndWaitWithException(GuiHelper.java:238)
	at org.openstreetmap.josm.gui.layer.LayerManager.removeLayer(LayerManager.java:247)
	at org.openstreetmap.josm.gui.dialogs.layer.DeleteLayerAction.actionPerformed(DeleteLayerAction.java:52)
	at javax.swing.AbstractButton.fireActionPerformed(Unknown Source)
	at javax.swing.AbstractButton$Handler.actionPerformed(Unknown Source)
	at javax.swing.DefaultButtonModel.fireActionPerformed(Unknown Source)
	at javax.swing.DefaultButtonModel.setPressed(Unknown Source)
	at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(Unknown Source)
	at java.awt.AWTEventMulticaster.mouseReleased(Unknown Source)
	at java.awt.Component.processMouseEvent(Unknown Source)
	at javax.swing.JComponent.processMouseEvent(Unknown Source)
	at java.awt.Component.processEvent(Unknown Source)
	at java.awt.Container.processEvent(Unknown Source)
	at java.awt.Component.dispatchEventImpl(Unknown Source)
	at java.awt.Container.dispatchEventImpl(Unknown Source)
	at java.awt.Component.dispatchEvent(Unknown Source)
	at java.awt.LightweightDispatcher.retargetMouseEvent(Unknown Source)
	at java.awt.LightweightDispatcher.processMouseEvent(Unknown Source)
	at java.awt.LightweightDispatcher.dispatchEvent(Unknown Source)
	at java.awt.Container.dispatchEventImpl(Unknown Source)
	at java.awt.Window.dispatchEventImpl(Unknown Source)
	at java.awt.Component.dispatchEvent(Unknown Source)
	at java.awt.EventQueue.dispatchEventImpl(Unknown Source)
	at java.awt.EventQueue.access$500(Unknown Source)
	at java.awt.EventQueue$3.run(Unknown Source)
	at java.awt.EventQueue$3.run(Unknown Source)
	at java.security.AccessController.doPrivileged(Native Method)
	at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(Unknown Source)
	at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(Unknown Source)
	at java.awt.EventQueue$4.run(Unknown Source)
	at java.awt.EventQueue$4.run(Unknown Source)
	at java.security.AccessController.doPrivileged(Native Method)
	at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(Unknown Source)
	at java.awt.EventQueue.dispatchEvent(Unknown Source)
	at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
	at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
	at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
	at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
	at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
	at java.awt.EventDispatchThread.run(Unknown Source)

[GerdP]

In 14502/josm:

fix #17064

[GerdP]

I was not able to reproduce the problem but I think I understand what was wrong.

[Don-vip]

In 14503/josm:

see #17064 - add non regression test

[GerdP]

Ticket #17066 has been marked as a duplicate of this ticket.