Index: src/org/openstreetmap/josm/gui/dialogs/SelectionListDialog.java
===================================================================
--- src/org/openstreetmap/josm/gui/dialogs/SelectionListDialog.java	(revision 3360)
+++ src/org/openstreetmap/josm/gui/dialogs/SelectionListDialog.java	(working copy)
@@ -528,7 +528,8 @@
                     break;
                 }
             }
-            while (history.size() > SELECTION_HISTORY_SIZE) {
+            int maxsize = Main.pref.getInteger("select.history-size", SELECTION_HISTORY_SIZE);
+            while (history.size() > maxsize) {
                 history.removeLast();
             }
         }