Index: trunk/src/org/openstreetmap/josm/data/Preferences.java
===================================================================
--- trunk/src/org/openstreetmap/josm/data/Preferences.java	(revision 8540)
+++ trunk/src/org/openstreetmap/josm/data/Preferences.java	(revision 8541)
@@ -45,4 +45,5 @@
 import javax.json.JsonObjectBuilder;
 import javax.json.JsonReader;
+import javax.json.JsonString;
 import javax.json.JsonValue;
 import javax.json.JsonWriter;
@@ -1361,5 +1362,11 @@
             ret = new HashMap(object.size());
             for (Entry<String, JsonValue> e: object.entrySet()) {
-                ret.put(e.getKey(), e.getValue().toString());
+                JsonValue value = e.getValue();
+                if (value instanceof JsonString) {
+                    // in some cases, when JsonValue.toString() is called, then additional quotation marks are left in value
+                    ret.put(e.getKey(), ((JsonString)value).getString());
+                } else {
+                    ret.put(e.getKey(), e.getValue().toString());
+                }
             }
         }