diff --git a/include/wx/treectrl.h b/include/wx/treectrl.h
index 129333ca74..b93495de26 100644
--- a/include/wx/treectrl.h
+++ b/include/wx/treectrl.h
@@ -33,20 +33,7 @@ class WXDLLIMPEXP_FWD_CORE wxImageList;
 class WXDLLIMPEXP_CORE wxTreeCtrlBase : public wxControl
 {
 public:
-    wxTreeCtrlBase()
-    {
-        m_imageListNormal =
-        m_imageListState = NULL;
-        m_ownsImageListNormal =
-        m_ownsImageListState = false;
-
-        // arbitrary default
-        m_spacing = 18;
-
-        // quick DoGetBestSize calculation
-        m_quickBestSize = true;
-    }
-
+    wxTreeCtrlBase();
     virtual ~wxTreeCtrlBase();
 
     // accessors
diff --git a/src/common/treebase.cpp b/src/common/treebase.cpp
index 483360b472..06e31ddbc3 100644
--- a/src/common/treebase.cpp
+++ b/src/common/treebase.cpp
@@ -167,6 +167,20 @@ wxTreeEvent::wxTreeEvent(const wxTreeEvent & event)
 // wxTreeCtrlBase
 // ----------------------------------------------------------------------------
 
+wxTreeCtrlBase::wxTreeCtrlBase()
+{
+    m_imageListNormal =
+    m_imageListState = NULL;
+    m_ownsImageListNormal =
+    m_ownsImageListState = false;
+
+    // arbitrary default
+    m_spacing = 18;
+
+    // quick DoGetBestSize calculation
+    m_quickBestSize = true;
+}
+
 wxTreeCtrlBase::~wxTreeCtrlBase()
 {
     if (m_ownsImageListNormal)