updater: use system look&feel

platform/bootstrap/src/com/intellij/idea/Main.java

@@ -155,6 +155,7 @@ public class Main {
                          patchCopy.getPath() + File.pathSeparator + log4jCopy.getPath(),
                          "-Djava.io.tmpdir=" + tempDir,
                          "-Didea.updater.log=" + PathManager.getLogPath(),
+                         "-Dswing.defaultlaf=" + UIManager.getSystemLookAndFeelClassName(),
                          "com.intellij.updater.Runner",
                          "install",
                          PathManager.getHomePath());

updater/src/com/intellij/updater/Runner.java

@@ -66,7 +66,6 @@ public class Runner {
     return logFolder;
   }
 
-//  public static void initLogger(String logFolder) {
   public static void initLogger() {
     if (logger == null) {
       String logFolder = getLogDir();
@@ -82,7 +81,6 @@ public class Runner {
       updateError.setFile(new File(logFolder, "idea_updater_error.log").getAbsolutePath());
       updateError.setLayout(new PatternLayout("%d{dd MMM yyyy HH:mm:ss} %-5p %C{1}.%M - %m%n"));
       updateError.setThreshold(Level.ERROR);
-      // The error(s) from an old run of the updater (if there were) could be found in idea_updater.log file
       updateError.setAppend(false);
       updateError.activateOptions();
 
@@ -198,17 +196,20 @@ public class Runner {
       in.close();
     }
 
-    SwingUtilities.invokeAndWait(new Runnable() {
-      @Override
-      public void run() {
-        try {
-          UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
+    // todo[r.sh] to delete in IDEA 14 (after a full circle of platform updates)
+    if (System.getProperty("swing.defaultlaf") == null) {
+      SwingUtilities.invokeAndWait(new Runnable() {
+        @Override
+        public void run() {
+          try {
+            UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
+          }
+          catch (Exception ignore) {
+            printStackTrace(ignore);
+          }
         }
-        catch (Exception ignore) {
-          printStackTrace(ignore);
-        }
-      }
-    });
+      });
+    }
 
     new SwingUpdaterUI(props.getProperty(OLD_BUILD_DESCRIPTION),
                   props.getProperty(NEW_BUILD_DESCRIPTION),