diff --git a/mozilla/js/rhino/toolsrc/org/mozilla/javascript/tools/debugger/Main.java b/mozilla/js/rhino/toolsrc/org/mozilla/javascript/tools/debugger/Main.java
index 97c17640874..35221a5cb5d 100644
--- a/mozilla/js/rhino/toolsrc/org/mozilla/javascript/tools/debugger/Main.java
+++ b/mozilla/js/rhino/toolsrc/org/mozilla/javascript/tools/debugger/Main.java
@@ -2233,7 +2233,7 @@ class SourceInfo {
         }
 
         int fnFirstLine = lines[0];
-        int fnEndLine = lines[0];
+        int fnEndLine = fnFirstLine + 1;
         for (int i = 1; i != lines.length; ++i) {
             int line = lines[i];
             if (line < fnFirstLine) {