From aa5ce7b95374baccf691bd00d544a43145a33b4d Mon Sep 17 00:00:00 2001
From: Sergey Evdokimov <sergey.evdokimov@jetbrains.com>
Date: Thu, 11 Apr 2013 15:20:31 +0400
Subject: [PATCH] IDEA-103600 UNDO error: Whenever I entered ctrl+z, this
 always worked. Since the last 2 EAP versions it is problematic

---
 .../encoding/EncodingProjectManagerImpl.java    | 17 +++++++++++------
 1 file changed, 11 insertions(+), 6 deletions(-)

diff --git a/platform/platform-impl/src/com/intellij/openapi/vfs/encoding/EncodingProjectManagerImpl.java b/platform/platform-impl/src/com/intellij/openapi/vfs/encoding/EncodingProjectManagerImpl.java
index 495d72e63178..826028cdd21b 100644
--- a/platform/platform-impl/src/com/intellij/openapi/vfs/encoding/EncodingProjectManagerImpl.java
+++ b/platform/platform-impl/src/com/intellij/openapi/vfs/encoding/EncodingProjectManagerImpl.java
@@ -210,17 +210,22 @@ public class EncodingProjectManagerImpl extends EncodingProjectManager {
 
   @Override
   public void setEncoding(@Nullable final VirtualFile virtualFileOrDir, @Nullable final Charset charset) {
+    Charset oldCharset;
+
     if (charset == null) {
-      myMapping.remove(virtualFileOrDir);
+      oldCharset = myMapping.remove(virtualFileOrDir);
     }
     else {
-      myMapping.put(virtualFileOrDir, charset);
+      oldCharset = myMapping.put(virtualFileOrDir, charset);
     }
-    myModificationCount++;
-    if (virtualFileOrDir != null) {
-      virtualFileOrDir.setCharset(virtualFileOrDir.getBOM() == null ? charset : null);
+
+    if (!Comparing.equal(oldCharset, charset)) {
+      myModificationCount++;
+      if (virtualFileOrDir != null) {
+        virtualFileOrDir.setCharset(virtualFileOrDir.getBOM() == null ? charset : null);
+      }
+      reloadAllFilesUnder(virtualFileOrDir);
     }
-    reloadAllFilesUnder(virtualFileOrDir);
   }
 
   private static void clearAndReload(@NotNull VirtualFile virtualFileOrDir) {