Index: trunk/src/org/openstreetmap/josm/gui/MapFrame.java
===================================================================
--- trunk/src/org/openstreetmap/josm/gui/MapFrame.java	(revision 4567)
+++ trunk/src/org/openstreetmap/josm/gui/MapFrame.java	(revision 4568)
@@ -490,5 +490,5 @@
             if (newMapMode != null) {
                 selectMapMode(newMapMode, newLayer); // it would be nice to select first supported mode when layer is first selected, but it don't work well with for example editgpx layer
-            } else {
+            } else if (mapMode != null) {
                 mapMode.exitMode(); // if new mode is null - simply exit from previous mode
             }