Index: /trunk/src/org/openstreetmap/josm/gui/preferences/PluginPreference.java
===================================================================
--- /trunk/src/org/openstreetmap/josm/gui/preferences/PluginPreference.java	(revision 935)
+++ /trunk/src/org/openstreetmap/josm/gui/preferences/PluginPreference.java	(revision 936)
@@ -347,5 +347,8 @@
 
 		String oldPlugins = Main.pref.get("plugins");
-		if (!plugins.equals(oldPlugins)) {
+		if(oldPlugins == null && plugins == null)
+			return;
+		if(plugins == null || oldPlugins == null || !plugins.equals(oldPlugins))
+		{
 			Main.pref.put("plugins", plugins);
 			gui.requiresRestart = true;