Index: trunk/src/org/openstreetmap/josm/gui/dialogs/ToggleDialog.java
===================================================================
--- trunk/src/org/openstreetmap/josm/gui/dialogs/ToggleDialog.java	(revision 4793)
+++ trunk/src/org/openstreetmap/josm/gui/dialogs/ToggleDialog.java	(revision 4794)
@@ -579,5 +579,5 @@
 
     protected void setIsDocked(boolean val) {
-        if(buttonsPanel != null) {
+        if(buttonsPanel != null && buttonsHide != null) {
             buttonsPanel.setVisible(val ? !isButtonHiding : true);
         }