Index: /trunk/src/org/openstreetmap/josm/gui/MapFrame.java
===================================================================
--- /trunk/src/org/openstreetmap/josm/gui/MapFrame.java	(revision 11535)
+++ /trunk/src/org/openstreetmap/josm/gui/MapFrame.java	(revision 11536)
@@ -119,5 +119,4 @@
 
     private final List<ToggleDialog> allDialogs = new ArrayList<>();
-    private final List<MapMode> mapModes = new ArrayList<>();
     private final List<IconToggleButton> allDialogButtons = new ArrayList<>();
     public final List<IconToggleButton> allMapModeButtons = new ArrayList<>();
@@ -388,7 +387,5 @@
 
     public void addMapMode(IconToggleButton b) {
-        if (b.getAction() instanceof MapMode) {
-            mapModes.add((MapMode) b.getAction());
-        } else
+        if (!(b.getAction() instanceof MapMode))
             throw new IllegalArgumentException("MapMode action must be subclass of MapMode");
         allMapModeButtons.add(b);