Index: /trunk/src/org/openstreetmap/josm/gui/dialogs/ToggleDialog.java
===================================================================
--- /trunk/src/org/openstreetmap/josm/gui/dialogs/ToggleDialog.java	(revision 5206)
+++ /trunk/src/org/openstreetmap/josm/gui/dialogs/ToggleDialog.java	(revision 5207)
@@ -666,5 +666,7 @@
         buttonHiding = val;
         PROP_BUTTON_HIDING.put(val);
-        buttonsHide.setIcon(ImageProvider.get("misc", val != ButtonHiddingType.ALWAYS_SHOWN ? "buttonhide" : "buttonshow"));
+        if (buttonsHide != null) {
+            buttonsHide.setIcon(ImageProvider.get("misc", val != ButtonHiddingType.ALWAYS_SHOWN ? "buttonhide" : "buttonshow"));
+        }
         if (buttonsPanel != null) {
             buttonsPanel.setVisible(val != ButtonHiddingType.ALWAYS_HIDDEN);