Index: trunk/src/org/openstreetmap/josm/gui/NavigatableComponent.java
===================================================================
--- trunk/src/org/openstreetmap/josm/gui/NavigatableComponent.java	(revision 9891)
+++ trunk/src/org/openstreetmap/josm/gui/NavigatableComponent.java	(revision 9893)
@@ -244,5 +244,6 @@
         if (nativeScaleLayer != null) {
             ScaleList scaleList = nativeScaleLayer.getNativeScales();
-            return scaleList.getSnapScale(scale, PROP_ZOOM_RATIO.get(), floor).getScale();
+            Scale snapscale = scaleList.getSnapScale(scale, PROP_ZOOM_RATIO.get(), floor);
+            return snapscale != null ? snapscale.getScale() : scale;
         } else {
             return scale;