diff --git a/docs/latex/wx/sizer.tex b/docs/latex/wx/sizer.tex
index e052026c43..7fcef683c5 100644
--- a/docs/latex/wx/sizer.tex
+++ b/docs/latex/wx/sizer.tex
@@ -254,9 +254,18 @@ see sample in the description of \helpref{wxBoxSizer}{wxboxsizer} if the window
 \func{void}{SetVirtualSizeHints}{\param{wxWindow* }{window}}
 
 Tell the sizer to set the minimal size of the {\it window} virtual area to match the sizer's
-minimal size.  For windows with managed scrollbars this will set them appropriately.
+minimal size. For windows with managed scrollbars this will set them appropriately.
 
 \wxheading{See also}
 
 \helpref{wxScrolledWindow::SetScrollbars}{wxscrolledwindowsetscrollbars}
 
+\membersection{wxSizer::Show}\label{wxsizershow}
+
+\func{void}{Show}{\param{wxWindow* }{window}, \param{bool }{show = TRUE}}
+
+\func{void}{Show}{\param{wxSizer* }{sizer}, \param{bool }{show = TRUE}}
+
+Shows or hides a window or sizer. To make a sizer item disappear or 
+reappear, use Show() followed by Layout().
+
diff --git a/docs/latex/wx/treeevt.tex b/docs/latex/wx/treeevt.tex
index 3889143b0f..98980ad290 100644
--- a/docs/latex/wx/treeevt.tex
+++ b/docs/latex/wx/treeevt.tex
@@ -20,8 +20,8 @@ functions that take a wxTreeEvent argument.
 
 \twocolwidtha{9cm}
 \begin{twocollist}\itemsep=0pt
-\twocolitem{{\bf EVT\_TREE\_BEGIN\_DRAG(id, func)}}{The user has started dragging an item with the left mouse button.}
-\twocolitem{{\bf EVT\_TREE\_BEGIN\_RDRAG(id, func)}}{The user has started dragging an item with the right mouse button.}
+\twocolitem{{\bf EVT\_TREE\_BEGIN\_DRAG(id, func)}}{The user has started dragging an item with the left mouse button. The event handler must call {\bf wxTreeEvent::Allow()} for the drag operation to continue.}
+\twocolitem{{\bf EVT\_TREE\_BEGIN\_RDRAG(id, func)}}{The user has started dragging an item with the right mouse button. The event handler must call {\bf wxTreeEvent::Allow()} for the drag operation to continue.}
 \twocolitem{{\bf EVT\_TREE\_BEGIN\_LABEL\_EDIT(id, func)}}{Begin editing a label. This can be prevented by calling \helpref{Veto()}{wxnotifyeventveto}.}
 \twocolitem{{\bf EVT\_TREE\_END\_DRAG(id, func)}}{The user has released the mouse after dragging an item.}
 \twocolitem{{\bf EVT\_TREE\_END\_LABEL\_EDIT(id, func)}}{The user has finished editing a label. This can be prevented by calling \helpref{Veto()}{wxnotifyeventveto}.}
diff --git a/docs/latex/wx/wxstring.tex b/docs/latex/wx/wxstring.tex
index 9ab8067f36..0ba4b7638a 100644
--- a/docs/latex/wx/wxstring.tex
+++ b/docs/latex/wx/wxstring.tex
@@ -660,7 +660,7 @@ If {\it fromEnd} is TRUE, reverse search direction.
 
 If {\bf caseSensitive}, comparison is case sensitive (the default).
 
-Returns the index of the first item matched, or NOT\_FOUND.
+Returns the index of the first item matched, or wxNOT\_FOUND.
 
 % TODO
 %\membersection{wxString::insert}\label{wxstringinsert}
diff --git a/include/wx/sizer.h b/include/wx/sizer.h
index 3857f28d25..993647edc7 100644
--- a/include/wx/sizer.h
+++ b/include/wx/sizer.h
@@ -80,6 +80,8 @@ public:
         { m_flag = flag; }
     void SetBorder( int border )
         { m_border = border; }
+    void Show ( bool show )
+        { m_show = show; }
 
     wxWindow *GetWindow() const
         { return m_window; }
@@ -95,6 +97,8 @@ public:
         { return m_flag; }
     int GetBorder() const
         { return m_border; }
+    bool IsShown() const
+        { return m_show; }
     wxObject* GetUserData()
         { return m_userData; }
     wxPoint GetPosition()
@@ -109,10 +113,15 @@ protected:
     int          m_option;
     int          m_border;
     int          m_flag;
+
+    // If TRUE, then this item is considered in the layout
+    // calculation.  Otherwise, it is skipped over. 
+    bool         m_show;
     // als: aspect ratio can always be calculated from m_size,
     //      but this would cause precision loss when the window
     //      is shrinked.  it is safer to preserve initial value.
     float        m_ratio;
+
     wxObject    *m_userData;
 
 private:
@@ -194,6 +203,21 @@ public:
 
     void SetDimension( int x, int y, int width, int height );
 
+    // Manage whether individual windows or sub-sizers are considered
+    // in the layout calculations or not.
+    void Show( wxWindow *window, bool show = TRUE );
+    void Hide( wxWindow *window )
+        { Show (window, FALSE); }
+    void Show( wxSizer *sizer, bool show = TRUE );
+    void Hide( wxSizer *sizer )
+        { Show (sizer, FALSE); }
+
+    bool IsShown( wxWindow *window );
+    bool IsShown( wxSizer *sizer );
+    
+    // Recursively call wxWindow::Show () on all sizer items.
+    void ShowItems (bool show);
+
 protected:
     wxSize  m_size;
     wxSize  m_minSize;
diff --git a/samples/controls/controls.cpp b/samples/controls/controls.cpp
index e29c0b5236..69df5f89a5 100644
--- a/samples/controls/controls.cpp
+++ b/samples/controls/controls.cpp
@@ -122,6 +122,8 @@ public:
     void OnTestButton(wxCommandEvent& event);
     void OnBmpButton(wxCommandEvent& event);
 
+    void OnSizerCheck (wxCommandEvent &event);
+
     wxListBox     *m_listbox,
                   *m_listboxSorted;
 #if wxUSE_CHOICE
@@ -153,6 +155,14 @@ public:
 
     wxStaticText  *m_label;
 
+    wxBoxSizer    *m_buttonSizer;
+    wxButton      *m_sizerBtn1;
+    wxButton      *m_sizerBtn2;
+    wxButton      *m_sizerBtn3;
+    wxButton      *m_sizerBtn4;
+    wxBoxSizer    *m_hsizer;
+    wxButton      *m_bigBtn;
+
 private:
     wxLog *m_logTargetOld;
 
@@ -403,6 +413,13 @@ const int  ID_BITMAP_BTN        = 192;
 
 const int  ID_CHANGE_COLOUR     = 200;
 
+const int  ID_SIZER_CHECK1      = 201;
+const int  ID_SIZER_CHECK2      = 202;
+const int  ID_SIZER_CHECK3      = 203;
+const int  ID_SIZER_CHECK4      = 204;
+const int  ID_SIZER_CHECK14     = 205;
+const int  ID_SIZER_CHECKBIG    = 206;
+
 BEGIN_EVENT_TABLE(MyPanel, wxPanel)
 EVT_SIZE      (                         MyPanel::OnSize)
 EVT_NOTEBOOK_PAGE_CHANGING(ID_NOTEBOOK, MyPanel::OnPageChanging)
@@ -465,6 +482,14 @@ EVT_CHECKBOX  (ID_CHANGE_COLOUR,        MyPanel::OnChangeColour)
 EVT_BUTTON    (ID_BUTTON_TEST1,         MyPanel::OnTestButton)
 EVT_BUTTON    (ID_BUTTON_TEST2,         MyPanel::OnTestButton)
 EVT_BUTTON    (ID_BITMAP_BTN,           MyPanel::OnBmpButton)
+
+EVT_CHECKBOX  (ID_SIZER_CHECK1,         MyPanel::OnSizerCheck)
+EVT_CHECKBOX  (ID_SIZER_CHECK2,         MyPanel::OnSizerCheck)
+EVT_CHECKBOX  (ID_SIZER_CHECK3,         MyPanel::OnSizerCheck)
+EVT_CHECKBOX  (ID_SIZER_CHECK4,         MyPanel::OnSizerCheck)
+EVT_CHECKBOX  (ID_SIZER_CHECK14,        MyPanel::OnSizerCheck)
+EVT_CHECKBOX  (ID_SIZER_CHECKBIG,       MyPanel::OnSizerCheck)
+
 END_EVENT_TABLE()
 
 BEGIN_EVENT_TABLE(MyButton, wxButton)
@@ -849,11 +874,53 @@ MyPanel::MyPanel( wxFrame *frame, int x, int y, int w, int h )
     panel = new wxPanel(m_notebook);
     panel->SetAutoLayout( TRUE );
 
-    wxBoxSizer *sizer = new wxBoxSizer( wxHORIZONTAL );
+    wxBoxSizer *sizer = new wxBoxSizer( wxVERTICAL );
 
-    sizer->Add( new wxButton(panel, -1, "Test Button &1" ), 3, wxALL, 10 );
-    sizer->Add( 20,20, 1 );
-    sizer->Add( new wxButton(panel, -1, "Multiline\nbutton" ), 3, wxGROW|wxALL, 10 );
+    wxStaticBoxSizer *csizer =
+      new wxStaticBoxSizer (new wxStaticBox (panel, -1, "Show Buttons"),
+			    wxHORIZONTAL );
+    
+    wxCheckBox *check1, *check2, *check3, *check4, *check14, *checkBig;
+    check1 = new wxCheckBox (panel, ID_SIZER_CHECK1, "1");
+    check1->SetValue (TRUE);
+    csizer->Add (check1);
+    check2 = new wxCheckBox (panel, ID_SIZER_CHECK2, "2");
+    check2->SetValue (TRUE);
+    csizer->Add (check2);
+    check3 = new wxCheckBox (panel, ID_SIZER_CHECK3, "3");
+    check3->SetValue (TRUE);
+    csizer->Add (check3);
+    check4 = new wxCheckBox (panel, ID_SIZER_CHECK4, "4");
+    check4->SetValue (TRUE);
+    csizer->Add (check4);
+    check14 = new wxCheckBox (panel, ID_SIZER_CHECK14, "1-4");
+    check14->SetValue (TRUE);
+    csizer->Add (check14);
+    checkBig = new wxCheckBox (panel, ID_SIZER_CHECKBIG, "Big");
+    checkBig->SetValue (TRUE);
+    csizer->Add (checkBig);
+    
+    sizer->Add (csizer);
+
+    m_hsizer = new wxBoxSizer( wxHORIZONTAL );
+
+    m_buttonSizer = new wxBoxSizer (wxVERTICAL);
+    
+    m_sizerBtn1 = new wxButton(panel, -1, "Test Button &1" );
+    m_buttonSizer->Add( m_sizerBtn1, 0, wxALL, 10 );
+    m_sizerBtn2 = new wxButton(panel, -1, "Test Button &2" );
+    m_buttonSizer->Add( m_sizerBtn2, 0, wxALL, 10 );
+    m_sizerBtn3 = new wxButton(panel, -1, "Test Button &3" );
+    m_buttonSizer->Add( m_sizerBtn3, 0, wxALL, 10 );
+    m_sizerBtn4 = new wxButton(panel, -1, "Test Button &4" );
+    m_buttonSizer->Add( m_sizerBtn4, 0, wxALL, 10 );
+
+    m_hsizer->Add (m_buttonSizer);
+    m_hsizer->Add( 20,20, 1 );
+    m_bigBtn = new wxButton(panel, -1, "Multiline\nbutton" );
+    m_hsizer->Add( m_bigBtn , 3, wxGROW|wxALL, 10 );
+
+    sizer->Add (m_hsizer, 1, wxGROW);
 
     panel->SetSizer( sizer );
 
@@ -1404,6 +1471,37 @@ void MyPanel::OnShowProgress( wxCommandEvent& WXUNUSED(event) )
 
 #endif // wxUSE_SPINBTN
 
+void MyPanel::OnSizerCheck( wxCommandEvent &event)
+{
+  switch (event.GetId ()) {
+  case ID_SIZER_CHECK1:
+    m_buttonSizer->Show (m_sizerBtn1, event.IsChecked ());
+    m_buttonSizer->Layout ();
+    break;
+  case ID_SIZER_CHECK2:
+    m_buttonSizer->Show (m_sizerBtn2, event.IsChecked ());
+    m_buttonSizer->Layout ();
+    break;
+  case ID_SIZER_CHECK3:
+    m_buttonSizer->Show (m_sizerBtn3, event.IsChecked ());
+    m_buttonSizer->Layout ();
+    break;
+  case ID_SIZER_CHECK4:
+    m_buttonSizer->Show (m_sizerBtn4, event.IsChecked ());
+    m_buttonSizer->Layout ();
+    break;
+  case ID_SIZER_CHECK14:
+    m_hsizer->Show (m_buttonSizer, event.IsChecked ());
+    m_hsizer->Layout ();
+    break;
+  case ID_SIZER_CHECKBIG:
+    m_hsizer->Show (m_bigBtn, event.IsChecked ());
+    m_hsizer->Layout ();
+    break;
+  }
+
+}
+
 MyPanel::~MyPanel()
 {
     //wxLog::RemoveTraceMask(_T("focus"));
diff --git a/src/common/sizer.cpp b/src/common/sizer.cpp
index 29d016bc98..d189ba79e4 100644
--- a/src/common/sizer.cpp
+++ b/src/common/sizer.cpp
@@ -50,6 +50,7 @@ wxSizerItem::wxSizerItem( int width, int height, int option, int flag, int borde
     m_option = option;
     m_border = border;
     m_flag = flag;
+    m_show = TRUE;		// Cannot be changed
     m_userData = userData;
 
     // minimal size is the initial size
@@ -69,6 +70,7 @@ wxSizerItem::wxSizerItem( wxWindow *window, int option, int flag, int border, wx
     m_option = option;
     m_border = border;
     m_flag = flag;
+    m_show = TRUE;
     m_userData = userData;
 
     // minimal size is the initial size
@@ -88,6 +90,7 @@ wxSizerItem::wxSizerItem( wxSizer *sizer, int option, int flag, int border, wxOb
     m_option = option;
     m_border = border;
     m_flag = flag;
+    m_show = TRUE;
     m_userData = userData;
 
     // minimal size is calculated later
@@ -638,6 +641,81 @@ bool wxSizer::DoSetItemMinSize( int pos, int width, int height )
     return TRUE;
 }
 
+void wxSizer::Show (wxWindow *window, bool show)
+{
+    wxNode *node = m_children.GetFirst();
+    while (node) {
+        wxSizerItem *item = (wxSizerItem*) node->Data();
+
+        if (item->IsWindow () && item->GetWindow () == window) {
+	  item->Show (show);
+	  window->Show (show);
+	  return;
+	}
+	node = node->Next();
+    }
+}
+
+void wxSizer::Show (wxSizer *sizer, bool show)
+{
+    wxNode *node = m_children.GetFirst();
+    while (node) {
+        wxSizerItem *item = (wxSizerItem*) node->Data();
+
+	if (item->IsSizer () && item->GetSizer () == sizer) {
+	    item->Show (show);
+	    sizer->ShowItems (show);
+	    return;
+	}
+	node = node->Next();
+    }
+}
+
+void wxSizer::ShowItems (bool show)
+{
+    wxNode *node = m_children.GetFirst();
+    while (node) {
+        wxSizerItem *item = (wxSizerItem*) node->Data();
+
+	if (item->IsWindow ())
+	    item->GetWindow()->Show (show);
+	else if (item->IsSizer ())
+	    item->GetSizer ()->ShowItems (show);
+
+	node = node->Next();
+    }
+}
+
+bool wxSizer::IsShown (wxWindow *window)
+{
+    wxNode *node = m_children.GetFirst();
+    while (node) {
+        wxSizerItem *item = (wxSizerItem*) node->Data();
+	
+	if (item->IsWindow () && item->GetWindow () == window) {
+	  return item->IsShown ();
+	}
+	node = node->Next();
+    }
+
+    return FALSE;
+}
+
+bool wxSizer::IsShown (wxSizer *sizer)
+{
+    wxNode *node = m_children.GetFirst();
+    while (node) {
+        wxSizerItem *item = (wxSizerItem*) node->Data();
+
+	if (item->IsSizer () && item->GetSizer () == sizer) {
+	  return item->IsShown ();
+	}
+	node = node->Next();
+    }
+
+    return FALSE;
+}
+
 //---------------------------------------------------------------------------
 // wxGridSizer
 //---------------------------------------------------------------------------
@@ -980,6 +1058,7 @@ void wxBoxSizer::RecalcSizes()
     while (node)
     {
         wxSizerItem *item = (wxSizerItem*) node->Data();
+	if (item->IsShown ()) {
 
         int weight = 1;
         if (item->GetOption())
@@ -1037,6 +1116,7 @@ void wxBoxSizer::RecalcSizes()
 
             pt.x += width;
         }
+	}
 
         node = node->Next();
     }
@@ -1059,7 +1139,7 @@ wxSize wxBoxSizer::CalcMin()
     while (node)
     {
         wxSizerItem *item = (wxSizerItem*) node->Data();
-        if (item->GetOption() != 0)
+        if (item->IsShown () && item->GetOption() != 0)
         {
             int stretch = item->GetOption();
             wxSize size( item->CalcMin() );
@@ -1079,7 +1159,7 @@ wxSize wxBoxSizer::CalcMin()
     while (node)
     {
         wxSizerItem *item = (wxSizerItem*) node->Data();
-
+	if (item->IsShown ()) {
         m_stretchable += item->GetOption();
 
         wxSize size( item->CalcMin() );
@@ -1115,7 +1195,7 @@ wxSize wxBoxSizer::CalcMin()
                 m_fixedHeight = wxMax( m_fixedHeight, size.y );
             }
         }
-
+	}
         node = node->Next();
     }