Index: trunk/src/org/openstreetmap/josm/gui/preferences/projection/ProjectionPreference.java
===================================================================
--- trunk/src/org/openstreetmap/josm/gui/preferences/projection/ProjectionPreference.java	(revision 12484)
+++ trunk/src/org/openstreetmap/josm/gui/preferences/projection/ProjectionPreference.java	(revision 12485)
@@ -273,5 +273,4 @@
 
     private static String projectionChoice;
-    private static final Map<String, Collection<String>> projectionChoicesSub = new HashMap<>();
     
     private static final StringProperty PROP_PROJECTION_DEFAULT = new StringProperty("projection.default", mercator.getId());
@@ -463,11 +462,10 @@
         }
         id = pc.getId();
+        Main.pref.putCollection("projection.sub."+id, pref);
         if (makeDefault) {
             PROP_PROJECTION_DEFAULT.put(id);
             PROP_SUB_PROJECTION_DEFAULT.put(pref);
-            Main.pref.putCollection("projection.default.sub."+id, pref);
         } else {
             projectionChoice = id;
-            projectionChoicesSub.put(id, pref);
         }
         pc.setPreferences(pref);
@@ -527,8 +525,5 @@
 
     private static Collection<String> getSubprojectionPreference(ProjectionChoice pc) {
-        Collection<String> sessionValue = projectionChoicesSub.get(pc.getId());
-        if (sessionValue != null)
-            return sessionValue;
-        return Main.pref.getCollection("projection.default.sub."+pc.getId(), null);
+        return Main.pref.getCollection("projection.sub."+pc.getId(), null);
     }