NPE in rev. 4332

[akks]

JOSM crashes with Null Pointer Exception after downloading two near map bbox-es with tracks.
The bug is introduced with r4332 and exception arises in trackVisibility[i++] expression.

Build-Date: 2011-08-22 15:51:46
Revision: 4332
Is-Local-Build: true

Identification: JOSM/1.5 (4332 SVN ru)
Memory Usage: 182 MB / 910 MB (113 MB allocated, but free)
Java version: 1.6.0_21, Sun Microsystems Inc., Java HotSpot(TM) 64-Bit Server VM
Operating system: Windows 7
Dataset consistency test: No problems found

java.lang.ArrayIndexOutOfBoundsException: 1
	at org.openstreetmap.josm.gui.layer.GpxLayer.paint(GpxLayer.java:626)
	at org.openstreetmap.josm.gui.MapView.paintLayer(MapView.java:451)
	at org.openstreetmap.josm.gui.MapView.paint(MapView.java:513)
	at javax.swing.JComponent.paintChildren(JComponent.java:862)
	at javax.swing.JSplitPane.paintChildren(JSplitPane.java:1030)
	at javax.swing.JComponent.paint(JComponent.java:1038)
	at javax.swing.JComponent.paintToOffscreen(JComponent.java:5124)
	at javax.swing.RepaintManager$PaintManager.paintDoubleBuffered(RepaintManager.java:1479)
	at javax.swing.RepaintManager$PaintManager.paint(RepaintManager.java:1410)
	at javax.swing.RepaintManager.paint(RepaintManager.java:1224)
	at javax.swing.JComponent._paintImmediately(JComponent.java:5072)
	at javax.swing.JComponent.paintImmediately(JComponent.java:4882)
	at javax.swing.RepaintManager.paintDirtyRegions(RepaintManager.java:785)
	at javax.swing.RepaintManager.paintDirtyRegions(RepaintManager.java:713)
	at javax.swing.RepaintManager.seqPaintDirtyRegions(RepaintManager.java:693)
	at javax.swing.SystemEventQueueUtilities$ComponentWorkRequest.run(SystemEventQueueUtilities.java:125)
	at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:209)
	at java.awt.EventQueue.dispatchEvent(EventQueue.java:597)
	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)

[xeen]

In [4334/josm]:

fix two NPEs in GpxLayer (fixes #6726) and also repaint the map when merging new GPX data