Index: /trunk/src/org/openstreetmap/josm/gui/history/HistoryBrowserModel.java
===================================================================
--- /trunk/src/org/openstreetmap/josm/gui/history/HistoryBrowserModel.java	(revision 9733)
+++ /trunk/src/org/openstreetmap/josm/gui/history/HistoryBrowserModel.java	(revision 9734)
@@ -625,8 +625,8 @@
         if (latest == null) {
             if (this.current == this.latest) {
-                this.current = history.getLatest();
+                this.current = history != null ? history.getLatest() : null;
             }
             if (this.reference == this.latest) {
-                this.reference = history.getLatest();
+                this.reference = history != null ? history.getLatest() : null;
             }
             this.latest = null;
@@ -644,6 +644,5 @@
 
     /**
-     * Removes this model as listener for data change and layer change
-     * events.
+     * Removes this model as listener for data change and layer change events.
      *
      */