Index: /trunk/src/org/openstreetmap/josm/data/preferences/ColorProperty.java
===================================================================
--- /trunk/src/org/openstreetmap/josm/data/preferences/ColorProperty.java	(revision 10921)
+++ /trunk/src/org/openstreetmap/josm/data/preferences/ColorProperty.java	(revision 10922)
@@ -21,5 +21,5 @@
      */
     public ColorProperty(String colName, String defaultValue) {
-        this(colName, ColorHelper.html2color(defaultValue));
+        this(colName, defaultValue == null ? null : ColorHelper.html2color(defaultValue));
     }
 
Index: /trunk/test/unit/org/openstreetmap/josm/data/PreferencesTest.groovy
===================================================================
--- /trunk/test/unit/org/openstreetmap/josm/data/PreferencesTest.groovy	(revision 10921)
+++ /trunk/test/unit/org/openstreetmap/josm/data/PreferencesTest.groovy	(revision 10922)
@@ -21,9 +21,9 @@
         assert new ColorProperty("foo", new Color(0x12345678, true)).get().alpha == 0x12
         assert Main.pref.putColor("bar", new Color(0x12345678, true))
-        assert new ColorProperty("bar", null).get().alpha == 0x12
+        assert new ColorProperty("bar", (String) null).get().alpha == 0x12
     }
 
     void testColorNameAlpha() {
-        assert new ColorProperty("foo", "bar", new Color(0x12345678, true)).get().alpha == 0x12
+        assert new ColorProperty("foo", new Color(0x12345678, true)).get().alpha == 0x12
         assert Main.pref.getDefaultColor("foo") == new Color(0x34, 0x56, 0x78, 0x12)
         assert Main.pref.getDefaultColor("foo").alpha == 0x12