diff --git a/src/html/helpfrm.cpp b/src/html/helpfrm.cpp
index 51d1bba8e9..fca7231c10 100644
--- a/src/html/helpfrm.cpp
+++ b/src/html/helpfrm.cpp
@@ -559,6 +559,8 @@ bool wxHtmlHelpFrame::Create(wxWindow* parent, wxWindowID id,
 
 wxHtmlHelpFrame::~wxHtmlHelpFrame()
 {
+    delete m_mergedIndex;
+    
     // PopEventHandler(); // wxhtmlhelpcontroller (not any more!)
     if (m_DataCreated)
         delete m_Data;