diff --git a/platform/platform-impl/src/com/intellij/openapi/editor/impl/RangeMarkerImpl.java b/platform/platform-impl/src/com/intellij/openapi/editor/impl/RangeMarkerImpl.java
index 9bb00e2e9ae3..fe0f72a9fb4a 100644
--- a/platform/platform-impl/src/com/intellij/openapi/editor/impl/RangeMarkerImpl.java
+++ b/platform/platform-impl/src/com/intellij/openapi/editor/impl/RangeMarkerImpl.java
@@ -37,6 +37,7 @@ public class RangeMarkerImpl extends UserDataHolderBase implements RangeMarkerEx
 
   private static final AtomicLong counter = new AtomicLong();
   private final long myId;
+  private volatile int modCount;
 
   protected RangeMarkerImpl(@NotNull DocumentEx document, int start, int end) {
     if (start < 0) {
@@ -102,6 +103,7 @@ public class RangeMarkerImpl extends UserDataHolderBase implements RangeMarkerEx
   }
 
   public final void documentChanged(DocumentEvent e) {
+    int modCount = this.modCount++;
     int oldStart = myStart;
     int oldEnd = myEnd;
     int docLength = myDocument.getTextLength();
@@ -119,7 +121,10 @@ public class RangeMarkerImpl extends UserDataHolderBase implements RangeMarkerEx
     changedUpdateImpl(e);
     if (isValid && (myStart > myEnd || myStart < 0 || myEnd > docLength)) {
       LOG.error("RangeMarker" + (isExpandToLeft ? "[" : "(") + oldStart + ", " + oldEnd + (isExpandToRight ? "]" : ")") +
-                " update failed. Event = " + e + ". Result[" + myStart + ", " + myEnd + "], doc length=" + docLength + "; "+getClass());
+                " update failed. Event = " + e + ". Result[" + myStart + ", " + myEnd + "], " +
+                "old doc length=" + docLength + "; real doc length = "+myDocument.getTextLength()+
+                "; old mod count="+modCount+"; mod count="+this.modCount+
+                "; "+getClass());
       isValid = false;
     }
   }