Index: /trunk/src/org/openstreetmap/josm/gui/preferences/ColorPreference.java
===================================================================
--- /trunk/src/org/openstreetmap/josm/gui/preferences/ColorPreference.java	(revision 3640)
+++ /trunk/src/org/openstreetmap/josm/gui/preferences/ColorPreference.java	(revision 3641)
@@ -85,5 +85,6 @@
                 colorKeyList_layer.put(getName(key), key);
             } else if(key.startsWith("mappaint.")) {
-                colorKeyList_mappaint.put(getName(key), key);
+                /* use getName(key)+key, as getName() may be ambiguous */
+                colorKeyList_mappaint.put(getName(key)+key, key);
             } else {
                 colorKeyList.put(getName(key), key);