Index: /trunk/src/org/openstreetmap/josm/gui/layer/markerlayer/Marker.java
===================================================================
--- /trunk/src/org/openstreetmap/josm/gui/layer/markerlayer/Marker.java	(revision 11849)
+++ /trunk/src/org/openstreetmap/josm/gui/layer/markerlayer/Marker.java	(revision 11850)
@@ -178,8 +178,7 @@
     /**
      * Plugins can add their Marker creation stuff at the bottom or top of this list
-     * (depending on whether they want to override default behaviour or just add new
-     * stuff).
-     */
-    public static final List<MarkerProducers> markerProducers = new LinkedList<>();
+     * (depending on whether they want to override default behaviour or just add new stuff).
+     */
+    private static final List<MarkerProducers> markerProducers = new LinkedList<>();
 
     // Add one Marker specifying the default behaviour.
@@ -222,4 +221,22 @@
     }
 
+    /**
+     * Add a new marker producers at the end of the JOSM list.
+     * @param mp a new marker producers
+     * @since 11850
+     */
+    public static void appendMarkerProducer(MarkerProducers mp) {
+        markerProducers.add(mp);
+    }
+
+    /**
+     * Add a new marker producers at the beginning of the JOSM list.
+     * @param mp a new marker producers
+     * @since 11850
+     */
+    public static void prependMarkerProducer(MarkerProducers mp) {
+        markerProducers.add(0, mp);
+    }
+
     private static URL uriToUrl(String uri, File relativePath) {
         URL url = null;