switching modes/tools after deleting last data layer while in "Draw Nodes" mode causes NPE

[Cobra]

How to reproduce:

• open josm with a gpx file
• create new data layer
• add a node or way, stay in "Draw Nodes" mode
• delete layer
• switch to a different mode or tool, e.g. select
• get a nice error in return
• click one of the buttons, try some other tool, get the same error

Repository Root: http://josm.openstreetmap.de/svn
Build-Date: 2010-05-09 01:31:34
Last Changed Author: jttt
Revision: 3223
Repository UUID: 0c6e7542-c601-0410-84e7-c038aed88b3b
URL: http://josm.openstreetmap.de/svn/trunk
Last Changed Date: 2010-05-08 19:29:43 +0200 (Sat, 08 May 2010)
Last Changed Rev: 3223

Memory Usage: 49 MB / 580 MB (15 MB allocated, but free)
Java version: 1.6.0_20, Sun Microsystems Inc., Java HotSpot(TM) Client VM
Operating system: Linux


Plugins: PicLayer,colorscheme,measurement,openstreetbugs,openvisible,remotecontrol,validator,wmsplugin
Plugin openstreetbugs (Version: 20696)
Plugin colorscheme (Version: 19426)
Plugin wmsplugin (Version: 20891)
Plugin openvisible (Version: 20067)
Plugin PicLayer (Version: 20217)
Plugin remotecontrol (Version: 19946)
Plugin validator (Version: 21177)
Plugin measurement (Version: 19681)

java.lang.NullPointerException
	at org.openstreetmap.josm.actions.mapmode.DrawAction.exitMode(DrawAction.java:244)
	at org.openstreetmap.josm.gui.MapFrame.selectMapMode(MapFrame.java:262)
	at org.openstreetmap.josm.actions.mapmode.MapMode.actionPerformed(MapMode.java:72)
	at javax.swing.SwingUtilities.notifyAction(SwingUtilities.java:1633)
	at javax.swing.JComponent.processKeyBinding(JComponent.java:2851)
	at javax.swing.KeyboardManager.fireBinding(KeyboardManager.java:267)
	at javax.swing.KeyboardManager.fireKeyboardAction(KeyboardManager.java:216)
	at javax.swing.JComponent.processKeyBindingsForAllComponents(JComponent.java:2928)
	at javax.swing.JComponent.processKeyBindings(JComponent.java:2920)
	at javax.swing.JComponent.processKeyEvent(JComponent.java:2814)
	at java.awt.Component.processEvent(Component.java:6040)
	at java.awt.Container.processEvent(Container.java:2041)
	at java.awt.Component.dispatchEventImpl(Component.java:4630)
	at java.awt.Container.dispatchEventImpl(Container.java:2099)
	at java.awt.Component.dispatchEvent(Component.java:4460)
	at java.awt.KeyboardFocusManager.redispatchEvent(KeyboardFocusManager.java:1850)
	at java.awt.DefaultKeyboardFocusManager.dispatchKeyEvent(DefaultKeyboardFocusManager.java:712)
	at java.awt.DefaultKeyboardFocusManager.preDispatchKeyEvent(DefaultKeyboardFocusManager.java:990)
	at java.awt.DefaultKeyboardFocusManager.typeAheadAssertions(DefaultKeyboardFocusManager.java:855)
	at java.awt.DefaultKeyboardFocusManager.dispatchEvent(DefaultKeyboardFocusManager.java:676)
	at java.awt.Component.dispatchEventImpl(Component.java:4502)
	at java.awt.Container.dispatchEventImpl(Container.java:2099)
	at java.awt.Window.dispatchEventImpl(Window.java:2478)
	at java.awt.Component.dispatchEvent(Component.java:4460)
	at java.awt.EventQueue.dispatchEvent(EventQueue.java:599)
	at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:269)
	at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:184)
	at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:174)
	at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:169)
	at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:161)
	at java.awt.EventDispatchThread.run(EventDispatchThread.java:122)

[stoecker]

(In [3320]) fix #5000 - NPE