Index: /applications/editors/josm/plugins/slippymap/src/org/openstreetmap/josm/plugins/slippymap/Constants.java
===================================================================
--- /applications/editors/josm/plugins/slippymap/src/org/openstreetmap/josm/plugins/slippymap/Constants.java	(revision 5685)
+++ /applications/editors/josm/plugins/slippymap/src/org/openstreetmap/josm/plugins/slippymap/Constants.java	(revision 5685)
@@ -0,0 +1,13 @@
+package org.openstreetmap.josm.plugins.slippymap;
+
+
+/**
+ * String constants
+ * 
+ * @author Hakan Tandogan <hakan@gurkensalat.com>
+ * 
+ */
+public interface Constants
+{
+    public static String PREFERENCE_PREFIX = "slippymap";
+}
Index: /applications/editors/josm/plugins/slippymap/src/org/openstreetmap/josm/plugins/slippymap/SlippyMapLayer.java
===================================================================
--- /applications/editors/josm/plugins/slippymap/src/org/openstreetmap/josm/plugins/slippymap/SlippyMapLayer.java	(revision 5684)
+++ /applications/editors/josm/plugins/slippymap/src/org/openstreetmap/josm/plugins/slippymap/SlippyMapLayer.java	(revision 5685)
@@ -466,5 +466,5 @@
     public void preferenceChanged(String key, String newValue)
     {
-        if (key.startsWith("slippymaplayer"))
+        if (key.startsWith(Constants.PREFERENCE_PREFIX))
         {
             System.err.println(this + ".preferenceChanged('" + key + "', '"