diff --git a/platform/util/src/com/intellij/util/text/MergingCharSequence.java b/platform/util/src/com/intellij/util/text/MergingCharSequence.java
index 0b7e4db0bb05..a0358ab8e86e 100644
--- a/platform/util/src/com/intellij/util/text/MergingCharSequence.java
+++ b/platform/util/src/com/intellij/util/text/MergingCharSequence.java
@@ -42,6 +42,7 @@ public class MergingCharSequence implements CharSequence {
 
   @Override
   public CharSequence subSequence(int start, int end) {
+    if (start == 0 && end == length()) return this;
     if (start < s1.length() && end < s1.length()) return s1.subSequence(start, end);
     if (start >= s1.length() && end >= s1.length()) return s2.subSequence(start - s1.length(), end - s1.length());
     return new MergingCharSequence(s1.subSequence(start, s1.length()), s2.subSequence(0, end - s1.length()));