Index: src/org/openstreetmap/josm/gui/preferences/PluginPreference.java
===================================================================
--- src/org/openstreetmap/josm/gui/preferences/PluginPreference.java	(revision 935)
+++ src/org/openstreetmap/josm/gui/preferences/PluginPreference.java	(working copy)
@@ -342,13 +342,14 @@
 		}
 		if(plugins.endsWith(","))
 			plugins = plugins.substring(0, plugins.length()-1);
-		if(plugins.length() == 0)
+		if(plugins.length() == 0) {
 			plugins = null;
-
-		String oldPlugins = Main.pref.get("plugins");
-		if (!plugins.equals(oldPlugins)) {
-			Main.pref.put("plugins", plugins);
-			gui.requiresRestart = true;
+		} else {
+			String oldPlugins = Main.pref.get("plugins");
+			if (!plugins.equals(oldPlugins)) {
+				Main.pref.put("plugins", plugins);
+				gui.requiresRestart = true;
+			}
 		}
 	}
 }