IllegalStateException upon attempting to combine any two ways

[Roadsguy]

What steps will reproduce the problem?

I don't know what exactly caused it, but it happened when I tried to combine two ways, and subsequently happened every time I tried to combine any way until I restarted JOSM.

What is the expected result?

The way combination conflict dialog would appear.

What happens instead?

Nothing happens to the ways, but the error report dialog appears instead every time.

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: 2016-11-06 20:18:38 +0100 (Sun, 06 Nov 2016)
Build-Date:2016-11-06 21:45:03
Revision:11223
Relative:URL: ^/trunk

Identification: JOSM/1.5 (11223 en) Windows 10 64-Bit
Memory Usage: 980 MB / 980 MB (489 MB allocated, but free)
Java version: 1.8.0_101-b13, Oracle Corporation, Java HotSpot(TM) 64-Bit Server VM
Screen: \Display0 1680x1050
Maximum Screen Size: 1680x1050
Dataset consistency test: No problems found

Plugins:
+ PicLayer (32796)
+ measurement (32936)
+ turnrestrictions (32796)

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
- E: Handled by bug report queue: java.lang.IllegalStateException: Tag collection does not include the selected value '2'.
- E: Handled by bug report queue: java.lang.IllegalStateException: Tag collection does not include the selected value '2'.
- E: Handled by bug report queue: java.lang.IllegalStateException: Tag collection does not include the selected value '2'.
- E: Handled by bug report queue: java.lang.IllegalStateException: Tag collection does not include the selected value '2'.
- E: Handled by bug report queue: java.lang.IllegalStateException: Tag collection does not include the selected value '2'.
- E: Handled by bug report queue: java.lang.IllegalStateException: Tag collection does not include the selected value '2'.


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

Warning issued by: BugReportExceptionHandler#handleException

=== STACK TRACE ===
Thread: AWT-EventQueue-0 (19) of main
java.lang.IllegalStateException: Tag collection does not include the selected value '2'.
	at org.openstreetmap.josm.gui.conflict.tags.MultiValueResolutionDecision.keepOne(MultiValueResolutionDecision.java:113)
	at org.openstreetmap.josm.gui.conflict.tags.TagConflictResolverModel.setValueAt(TagConflictResolverModel.java:155)
	at javax.swing.JTable.setValueAt(Unknown Source)
	at javax.swing.JTable.editingStopped(Unknown Source)
	at javax.swing.AbstractCellEditor.fireEditingStopped(Unknown Source)
	at javax.swing.AbstractCellEditor.stopCellEditing(Unknown Source)
	at javax.swing.JTable.columnMarginChanged(Unknown Source)
	at javax.swing.table.DefaultTableColumnModel.fireColumnMarginChanged(Unknown Source)
	at javax.swing.table.DefaultTableColumnModel.propertyChange(Unknown Source)
	at java.beans.PropertyChangeSupport.fire(Unknown Source)
	at java.beans.PropertyChangeSupport.firePropertyChange(Unknown Source)
	at javax.swing.event.SwingPropertyChangeSupport.firePropertyChange(Unknown Source)
	at java.beans.PropertyChangeSupport.firePropertyChange(Unknown Source)
	at javax.swing.table.TableColumn.firePropertyChange(Unknown Source)
	at javax.swing.table.TableColumn.firePropertyChange(Unknown Source)
	at javax.swing.table.TableColumn.setWidth(Unknown Source)
	at javax.swing.JTable$2.setSizeAt(Unknown Source)
	at javax.swing.JTable$5.setSizeAt(Unknown Source)
	at javax.swing.JTable.adjustSizes(Unknown Source)
	at javax.swing.JTable.adjustSizes(Unknown Source)
	at javax.swing.JTable.setWidthsFromPreferredWidths(Unknown Source)
	at javax.swing.JTable.doLayout(Unknown Source)
	at java.awt.Container.validateTree(Unknown Source)
	at java.awt.Container.validateTree(Unknown Source)
	at java.awt.Container.validateTree(Unknown Source)
	at java.awt.Container.validateTree(Unknown Source)
	at java.awt.Container.validateTree(Unknown Source)
	at java.awt.Container.validateTree(Unknown Source)
	at java.awt.Container.validateTree(Unknown Source)
	at java.awt.Container.validateTree(Unknown Source)
	at java.awt.Container.validateTree(Unknown Source)
	at java.awt.Container.validate(Unknown Source)
	at org.openstreetmap.josm.gui.conflict.tags.CombinePrimitiveResolverDialog.prepareGUIBeforeConflictResolutionStarts(CombinePrimitiveResolverDialog.java:328)
	at org.openstreetmap.josm.gui.conflict.tags.CombinePrimitiveResolverDialog.setVisible(CombinePrimitiveResolverDialog.java:348)
	at org.openstreetmap.josm.gui.conflict.tags.CombinePrimitiveResolverDialog.launchIfNecessary(CombinePrimitiveResolverDialog.java:516)
	at org.openstreetmap.josm.actions.CombineWayAction.combineWaysWorker(CombineWayAction.java:183)
	at org.openstreetmap.josm.actions.CombineWayAction.actionPerformed(CombineWayAction.java:223)
	at javax.swing.SwingUtilities.notifyAction(Unknown Source)
	at javax.swing.JComponent.processKeyBinding(Unknown Source)
	at javax.swing.KeyboardManager.fireBinding(Unknown Source)
	at javax.swing.KeyboardManager.fireKeyboardAction(Unknown Source)
	at javax.swing.JComponent.processKeyBindingsForAllComponents(Unknown Source)
	at javax.swing.JComponent.processKeyBindings(Unknown Source)
	at javax.swing.JComponent.processKeyEvent(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.KeyboardFocusManager.redispatchEvent(Unknown Source)
	at java.awt.DefaultKeyboardFocusManager.dispatchKeyEvent(Unknown Source)
	at java.awt.DefaultKeyboardFocusManager.preDispatchKeyEvent(Unknown Source)
	at java.awt.DefaultKeyboardFocusManager.typeAheadAssertions(Unknown Source)
	at java.awt.DefaultKeyboardFocusManager.dispatchEvent(Unknown Source)
	at java.awt.Component.dispatchEventImpl(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)

[Don-vip]

Closed as duplicate of #12630.