diff --git a/docs/doxygen/overviews/commondialogs.h b/docs/doxygen/overviews/commondialogs.h
index bd05480a1d..4cdf52abd2 100644
--- a/docs/doxygen/overviews/commondialogs.h
+++ b/docs/doxygen/overviews/commondialogs.h
@@ -48,11 +48,11 @@ controls to select a precise colour, and add it to the custom colour palette.
 
 Under non-MS Windows platforms, the colour selector is a simulation of most of
 the features of the MS Windows selector. Two palettes of 48 standard and 16
-custom colours are presented, with the right-hand area containing three sliders
-for the user to select a colour from red, green and blue components. This
+custom colours are presented, with the right-hand area containing three or four sliders
+for the user to select a colour from red, green, blue and opacity (optionally) components. This
 colour may be added to the custom colour palette, and will replace either the
 currently selected custom colour, or the first one in the palette if none is
-selected. The RGB colour sliders are not optional in the generic colour
+selected. The RGB or ARGB colour sliders are not optional in the generic colour
 selector. The generic colour selector is also available under MS Windows; use
 the name wxGenericColourDialog.
 
diff --git a/include/wx/colourdata.h b/include/wx/colourdata.h
index dfaab13f26..d05a9a37b4 100644
--- a/include/wx/colourdata.h
+++ b/include/wx/colourdata.h
@@ -26,6 +26,8 @@ public:
 
     void SetChooseFull(bool flag) { m_chooseFull = flag; }
     bool GetChooseFull() const { return m_chooseFull; }
+    void SetChooseAlpha(bool flag) { m_chooseAlpha = flag; }
+    bool GetChooseAlpha() const { return m_chooseAlpha; }
     void SetColour(const wxColour& colour) { m_dataColour = colour; }
     const wxColour& GetColour() const { return m_dataColour; }
     wxColour& GetColour() { return m_dataColour; }
@@ -45,6 +47,9 @@ public:
     wxColour        m_custColours[NUM_CUSTOM];
     bool            m_chooseFull;
 
+protected:
+    bool            m_chooseAlpha;
+
     wxDECLARE_DYNAMIC_CLASS(wxColourData);
 };
 
diff --git a/include/wx/generic/colrdlgg.h b/include/wx/generic/colrdlgg.h
index 4399baa436..086ce5b25b 100644
--- a/include/wx/generic/colrdlgg.h
+++ b/include/wx/generic/colrdlgg.h
@@ -14,18 +14,18 @@
 #include "wx/gdicmn.h"
 #include "wx/dialog.h"
 
-#define wxID_ADD_CUSTOM     3000
-
 #if wxUSE_SLIDER
-
-    #define wxID_RED_SLIDER     3001
-    #define wxID_GREEN_SLIDER   3002
-    #define wxID_BLUE_SLIDER    3003
-
     class WXDLLIMPEXP_FWD_CORE wxSlider;
-
 #endif // wxUSE_SLIDER
 
+// Preview with opacity is possible only
+// if wxGCDC and wxStaticBitmap are available.
+#define wxCLRDLGG_USE_PREVIEW_WITH_ALPHA (wxUSE_GRAPHICS_CONTEXT && wxUSE_STATBMP)
+
+#if wxCLRDLGG_USE_PREVIEW_WITH_ALPHA
+class wxStaticBitmap;
+#endif // wxCLRDLGG_USE_PREVIEW_WITH_ALPHA
+
 class WXDLLIMPEXP_CORE wxGenericColourDialog : public wxDialog
 {
 public:
@@ -43,13 +43,18 @@ public:
     // Internal functions
     void OnMouseEvent(wxMouseEvent& event);
     void OnPaint(wxPaintEvent& event);
+#if wxCLRDLGG_USE_PREVIEW_WITH_ALPHA
+    void OnCustomColourMouseClick(wxMouseEvent& event);
+#endif // wxCLRDLGG_USE_PREVIEW_WITH_ALPHA
 
     virtual void CalculateMeasurements();
     virtual void CreateWidgets();
     virtual void InitializeColours();
 
     virtual void PaintBasicColours(wxDC& dc);
-    virtual void PaintCustomColours(wxDC& dc);
+#if !wxCLRDLGG_USE_PREVIEW_WITH_ALPHA
+    virtual void PaintCustomColours(wxDC& dc, int clrIndex = -1);
+#endif // !wxCLRDLGG_USE_PREVIEW_WITH_ALPHA
     virtual void PaintCustomColour(wxDC& dc);
     virtual void PaintHighlight(wxDC& dc, bool draw);
 
@@ -62,10 +67,15 @@ public:
     void OnRedSlider(wxCommandEvent& event);
     void OnGreenSlider(wxCommandEvent& event);
     void OnBlueSlider(wxCommandEvent& event);
+    void OnAlphaSlider(wxCommandEvent& event);
 #endif // wxUSE_SLIDER
 
     void OnCloseWindow(wxCloseEvent& event);
 
+#if wxCLRDLGG_USE_PREVIEW_WITH_ALPHA
+    void DoPreviewBitmap(wxBitmap& bmp, const wxColour& colour);
+#endif // wxCLRDLGG_USE_PREVIEW_WITH_ALPHA
+
 protected:
     wxColourData m_colourData;
 
@@ -75,10 +85,7 @@ protected:
     wxRect m_singleCustomColourRect;
 
     // Size of each colour rectangle
-    wxPoint m_smallRectangleSize;
-
-    // For single customizable colour
-    wxPoint m_customRectangleSize;
+    wxSize m_smallRectangleSize;
 
     // Grid spacing (between rectangles)
     int m_gridSpacing;
@@ -100,7 +107,14 @@ protected:
     wxSlider *m_redSlider;
     wxSlider *m_greenSlider;
     wxSlider *m_blueSlider;
+    wxSlider *m_alphaSlider;
 #endif // wxUSE_SLIDER
+#if wxCLRDLGG_USE_PREVIEW_WITH_ALPHA
+    // Bitmap to preview selected colour (with alpha channel)
+    wxStaticBitmap *m_customColourBmp;
+    // Bitmaps to preview custom colours (with alpha channel)
+    wxStaticBitmap *m_customColoursBmp[16];
+#endif // wxCLRDLGG_USE_PREVIEW_WITH_ALPHA
 
     int m_buttonY;
 
diff --git a/samples/dialogs/dialogs.cpp b/samples/dialogs/dialogs.cpp
index ec3f4ab0bc..dfa711bf41 100644
--- a/samples/dialogs/dialogs.cpp
+++ b/samples/dialogs/dialogs.cpp
@@ -221,6 +221,7 @@ wxBEGIN_EVENT_TABLE(MyFrame, wxFrame)
 
 #if USE_COLOURDLG_GENERIC
     EVT_MENU(DIALOGS_CHOOSE_COLOUR_GENERIC,         MyFrame::ChooseColourGeneric)
+    EVT_MENU(DIALOGS_CHOOSE_COLOUR_GENERIC_ALPHA,   MyFrame::ChooseColourGeneric)
 #endif // USE_COLOURDLG_GENERIC
 
 #if wxUSE_PROGRESSDLG
@@ -400,7 +401,10 @@ bool MyApp::OnInit()
     #endif // USE_COLOURDLG_GENERIC || USE_FONTDLG_GENERIC
 
     #if USE_COLOURDLG_GENERIC
-        choices_menu->Append(DIALOGS_CHOOSE_COLOUR_GENERIC, wxT("&Choose colour (generic)"));
+        wxMenu *colourGeneric_menu = new wxMenu;
+        colourGeneric_menu->Append(DIALOGS_CHOOSE_COLOUR_GENERIC, wxT("&No opacity"));
+        colourGeneric_menu->Append(DIALOGS_CHOOSE_COLOUR_GENERIC_ALPHA, wxT("&With opacity"));
+        choices_menu->Append(wxID_ANY, wxT("&Choose colour (generic)"), colourGeneric_menu);
     #endif // USE_COLOURDLG_GENERIC
 
     #if USE_FONTDLG_GENERIC
@@ -741,21 +745,18 @@ void MyFrame::GetColour(wxCommandEvent& WXUNUSED(event))
 
 
 #if USE_COLOURDLG_GENERIC
-void MyFrame::ChooseColourGeneric(wxCommandEvent& WXUNUSED(event))
+void MyFrame::ChooseColourGeneric(wxCommandEvent& event)
 {
     m_clrData.SetColour(m_canvas->GetBackgroundColour());
 
     //FIXME:TODO:This has no effect...
     m_clrData.SetChooseFull(true);
+    m_clrData.SetChooseAlpha(event.GetId() == DIALOGS_CHOOSE_COLOUR_GENERIC_ALPHA);
 
-    for (int i = 0; i < 16; i++)
+    for (int i = 0; i < wxColourData::NUM_CUSTOM; i++)
     {
-        wxColour colour(
-            (unsigned char)(i*16),
-            (unsigned char)(i*16),
-            (unsigned char)(i*16)
-        );
-        m_clrData.SetCustomColour(i, colour);
+        unsigned char n = i*(256/wxColourData::NUM_CUSTOM);
+        m_clrData.SetCustomColour(i, wxColour(n, n, n));
     }
 
     wxGenericColourDialog *dialog = new wxGenericColourDialog(this, &m_clrData);
diff --git a/samples/dialogs/dialogs.h b/samples/dialogs/dialogs.h
index bf174f8dbf..3d8647399b 100644
--- a/samples/dialogs/dialogs.h
+++ b/samples/dialogs/dialogs.h
@@ -536,6 +536,7 @@ enum
     DIALOGS_CHOOSE_COLOUR = wxID_HIGHEST,
     DIALOGS_GET_COLOUR,
     DIALOGS_CHOOSE_COLOUR_GENERIC,
+    DIALOGS_CHOOSE_COLOUR_GENERIC_ALPHA,
     DIALOGS_CHOOSE_FONT,
     DIALOGS_CHOOSE_FONT_GENERIC,
     DIALOGS_MESSAGE_BOX,
diff --git a/src/common/colourdata.cpp b/src/common/colourdata.cpp
index 1748076863..3ad774195f 100644
--- a/src/common/colourdata.cpp
+++ b/src/common/colourdata.cpp
@@ -25,6 +25,7 @@ wxIMPLEMENT_DYNAMIC_CLASS(wxColourData, wxObject);
 wxColourData::wxColourData()
 {
     m_chooseFull = false;
+    m_chooseAlpha = false;
     m_dataColour.Set(0,0,0);
     // m_custColours are wxNullColours initially
 }
@@ -61,6 +62,7 @@ wxColourData& wxColourData::operator=(const wxColourData& data)
 
     m_dataColour = data.m_dataColour;
     m_chooseFull = data.m_chooseFull;
+    m_chooseAlpha = data.m_chooseAlpha;
 
     return *this;
 }
@@ -85,6 +87,9 @@ wxString wxColourData::ToString() const
             str += clr.GetAsString(wxC2S_HTML_SYNTAX);
     }
 
+    str.Append(wxCOL_DATA_SEP);
+    str.Append(m_chooseAlpha ? '1' : '0');
+
     return str;
 }
 
@@ -102,6 +107,14 @@ bool wxColourData::FromString(const wxString& str)
         else
             success = m_custColours[i].Set(token);
     }
+
+    if ( success )
+    {
+        token = tokenizer.GetNextToken();
+        m_chooseAlpha = token == wxS("1");
+        success = m_chooseAlpha || token == wxS("0");
+    }
+
     return success;
 }
 
diff --git a/src/generic/colrdlgg.cpp b/src/generic/colrdlgg.cpp
index be1dc18577..f503201059 100644
--- a/src/generic/colrdlgg.cpp
+++ b/src/generic/colrdlgg.cpp
@@ -37,6 +37,19 @@
 #include "wx/colourdata.h"
 #include "wx/generic/colrdlgg.h"
 
+#if wxCLRDLGG_USE_PREVIEW_WITH_ALPHA
+#include "wx/statbmp.h"
+#include "wx/dcmemory.h"
+#include "wx/dcgraph.h"
+#endif // wxCLRDLGG_USE_PREVIEW_WITH_ALPHA
+
+#define wxID_ADD_CUSTOM     3000
+#if wxUSE_SLIDER
+    #define wxID_RED_SLIDER     3001
+    #define wxID_GREEN_SLIDER   3002
+    #define wxID_BLUE_SLIDER    3003
+#endif // wxUSE_SLIDER
+
 wxIMPLEMENT_DYNAMIC_CLASS(wxGenericColourDialog, wxDialog);
 
 wxBEGIN_EVENT_TABLE(wxGenericColourDialog, wxDialog)
@@ -164,7 +177,7 @@ int wxGenericColourDialog::ShowModal()
 // Internal functions
 void wxGenericColourDialog::OnMouseEvent(wxMouseEvent& event)
 {
-  if (event.ButtonDown(1))
+  if (event.ButtonDown(wxMOUSE_BTN_LEFT))
   {
     int x = (int)event.GetX();
     int y = (int)event.GetY();
@@ -177,6 +190,8 @@ void wxGenericColourDialog::OnMouseEvent(wxMouseEvent& event)
       int ptr = (int)(selX + selY*8);
       OnBasicColourClick(ptr);
     }
+    // wxStaticBitmap (used to ARGB preview) events are handled in the dedicated handler.
+#if !wxCLRDLGG_USE_PREVIEW_WITH_ALPHA
     else if ((x >= m_customColoursRect.x && x <= (m_customColoursRect.x + m_customColoursRect.width)) &&
         (y >= m_customColoursRect.y && y <= (m_customColoursRect.y + m_customColoursRect.height)))
     {
@@ -185,6 +200,7 @@ void wxGenericColourDialog::OnMouseEvent(wxMouseEvent& event)
       int ptr = (int)(selX + selY*8);
       OnCustomColourClick(ptr);
     }
+#endif
     else
         event.Skip();
   }
@@ -192,22 +208,43 @@ void wxGenericColourDialog::OnMouseEvent(wxMouseEvent& event)
       event.Skip();
 }
 
+#if wxCLRDLGG_USE_PREVIEW_WITH_ALPHA
+void wxGenericColourDialog::OnCustomColourMouseClick(wxMouseEvent& event)
+{
+    // Find index of custom colour
+    // and call the handler.
+    for (int i = 0; i < WXSIZEOF(m_customColoursBmp); i++)
+    {
+        if ( m_customColoursBmp[i]->GetId() == event.GetId() )
+        {
+              OnCustomColourClick(i);
+              return;
+        }
+    }
+
+    event.Skip();
+}
+#endif // wxCLRDLGG_USE_PREVIEW_WITH_ALPHA
+
 void wxGenericColourDialog::OnPaint(wxPaintEvent& WXUNUSED(event))
 {
     wxPaintDC dc(this);
 
     PaintBasicColours(dc);
-    PaintCustomColours(dc);
+    // wxStaticBitmap controls are updated on their own.
+#if !wxCLRDLGG_USE_PREVIEW_WITH_ALPHA
+    PaintCustomColours(dc, -1);
     PaintCustomColour(dc);
+#endif // !wxCLRDLGG_USE_PREVIEW_WITH_ALPHA
     PaintHighlight(dc, true);
 }
 
 void wxGenericColourDialog::CalculateMeasurements()
 {
-    m_smallRectangleSize.x = 18;
-    m_smallRectangleSize.y = 14;
-    m_customRectangleSize.x = 40;
-    m_customRectangleSize.y = 40;
+    // For single customizable colour
+    const wxSize customRectangleSize(40, 40);
+
+    m_smallRectangleSize.Set(18, 14);
 
     m_gridSpacing = 6;
     m_sectionSpacing = 15;
@@ -224,8 +261,7 @@ void wxGenericColourDialog::CalculateMeasurements()
 
     m_singleCustomColourRect.x = m_customColoursRect.width + m_customColoursRect.x + m_sectionSpacing;
     m_singleCustomColourRect.y = 80;
-    m_singleCustomColourRect.width = m_customRectangleSize.x;
-    m_singleCustomColourRect.height = m_customRectangleSize.y;
+    m_singleCustomColourRect.SetSize(customRectangleSize);
 
     m_okButtonX = 10;
     m_customButtonX = m_singleCustomColourRect.x ;
@@ -236,6 +272,33 @@ void wxGenericColourDialog::CreateWidgets()
 {
     wxBeginBusyCursor();
 
+#if wxCLRDLGG_USE_PREVIEW_WITH_ALPHA
+    // Bitmap to preview selected colour (with alpha channel)
+    wxBitmap customColourBmp(m_singleCustomColourRect.GetSize(), 32);
+    customColourBmp.UseAlpha();
+    DoPreviewBitmap(customColourBmp, m_colourData.GetColour());
+    m_customColourBmp = new wxStaticBitmap(this, wxID_ANY, customColourBmp,
+                                           m_singleCustomColourRect.GetLeftTop(),
+                                           m_singleCustomColourRect.GetSize(),
+                                           wxBORDER_SUNKEN);
+
+    // 16 bitmaps to preview custom colours (with alpha channel)
+    for (int i = 0; i < WXSIZEOF(m_customColoursBmp); i++)
+    {
+        int x = ((i % 8)*(m_smallRectangleSize.x+m_gridSpacing)) + m_customColoursRect.x;
+        int y = ((i / 8)*(m_smallRectangleSize.y+m_gridSpacing)) + m_customColoursRect.y;
+
+        wxBitmap bmp(m_smallRectangleSize, 32);
+        bmp.UseAlpha();
+        DoPreviewBitmap(bmp, m_customColours[i]);
+        m_customColoursBmp[i] = new wxStaticBitmap(this, wxID_ANY, bmp,
+                                                   wxPoint(x, y), m_smallRectangleSize);
+        m_customColoursBmp[i]->Bind(wxEVT_LEFT_DOWN,
+                                    &wxGenericColourDialog::OnCustomColourMouseClick, this);
+
+    }
+#endif // wxCLRDLGG_USE_PREVIEW_WITH_ALPHA
+
     wxBoxSizer *topSizer = new wxBoxSizer( wxVERTICAL );
 
     const int sliderHeight = 160;
@@ -244,23 +307,53 @@ void wxGenericColourDialog::CreateWidgets()
 #if wxUSE_SLIDER
     const int sliderX = m_singleCustomColourRect.x + m_singleCustomColourRect.width + m_sectionSpacing;
 
-    m_redSlider = new wxSlider(this, wxID_RED_SLIDER, m_colourData.m_dataColour.Red(), 0, 255,
+    wxColour c = m_colourData.GetColour();
+    m_redSlider = new wxSlider(this, wxID_RED_SLIDER, c.Red(), 0, 255,
         wxDefaultPosition, wxSize(wxDefaultCoord, sliderHeight), wxSL_VERTICAL|wxSL_LABELS|wxSL_INVERSE);
-    m_greenSlider = new wxSlider(this, wxID_GREEN_SLIDER, m_colourData.m_dataColour.Green(), 0, 255,
+    m_greenSlider = new wxSlider(this, wxID_GREEN_SLIDER, c.Green(), 0, 255,
         wxDefaultPosition, wxSize(wxDefaultCoord, sliderHeight), wxSL_VERTICAL|wxSL_LABELS|wxSL_INVERSE);
-    m_blueSlider = new wxSlider(this, wxID_BLUE_SLIDER, m_colourData.m_dataColour.Blue(), 0, 255,
+    m_blueSlider = new wxSlider(this, wxID_BLUE_SLIDER, c.Blue(), 0, 255,
         wxDefaultPosition, wxSize(wxDefaultCoord, sliderHeight), wxSL_VERTICAL|wxSL_LABELS|wxSL_INVERSE);
+    if ( m_colourData.GetChooseAlpha() )
+    {
+        m_alphaSlider = new wxSlider(this, wxID_ANY, c.Alpha(), 0, 255,
+            wxDefaultPosition, wxSize(wxDefaultCoord, sliderHeight), wxSL_VERTICAL|wxSL_LABELS|wxSL_INVERSE);
+        m_alphaSlider->Bind(wxEVT_SLIDER, &wxGenericColourDialog::OnAlphaSlider, this);
+    }
+    else
+    {
+        m_alphaSlider = NULL;
+    }
 
     wxBoxSizer *sliderSizer = new wxBoxSizer( wxHORIZONTAL );
 
     sliderSizer->Add(sliderX, sliderHeight );
 
+    const wxSizerFlags sliderLabelFlags = wxSizerFlags().Right().Border();
+    const wxSizerFlags onesliderFlags = wxSizerFlags().CenterHorizontal();
     const wxSizerFlags sliderFlags
         = wxSizerFlags().CentreVertical().DoubleBorder();
 
-    sliderSizer->Add(m_redSlider, sliderFlags);
-    sliderSizer->Add(m_greenSlider, sliderFlags);
-    sliderSizer->Add(m_blueSlider, sliderFlags);
+    wxBoxSizer *redSliderSizer = new wxBoxSizer(wxVERTICAL);
+    redSliderSizer->Add(new wxStaticText(this, wxID_ANY, _("Red:")), sliderLabelFlags);
+    redSliderSizer->Add(m_redSlider, onesliderFlags);
+    wxBoxSizer *greenSliderSizer = new wxBoxSizer(wxVERTICAL);
+    greenSliderSizer->Add(new wxStaticText(this, wxID_ANY, _("Green:")), sliderLabelFlags);
+    greenSliderSizer->Add(m_greenSlider, onesliderFlags);
+    wxBoxSizer *blueSliderSizer = new wxBoxSizer(wxVERTICAL);
+    blueSliderSizer->Add(new wxStaticText(this, wxID_ANY, _("Blue:")), sliderLabelFlags);
+    blueSliderSizer->Add(m_blueSlider, onesliderFlags);
+
+    sliderSizer->Add(redSliderSizer, sliderFlags);
+    sliderSizer->Add(greenSliderSizer, sliderFlags);
+    sliderSizer->Add(blueSliderSizer, sliderFlags);
+    if ( m_colourData.GetChooseAlpha() )
+    {
+        wxBoxSizer *alphaSliderSizer = new wxBoxSizer(wxVERTICAL);
+        alphaSliderSizer->Add(new wxStaticText(this, wxID_ANY, _("Opacity:")), sliderLabelFlags);
+        alphaSliderSizer->Add(m_alphaSlider, onesliderFlags);
+        sliderSizer->Add(alphaSliderSizer, sliderFlags);
+    }
 
     topSizer->Add(sliderSizer, wxSizerFlags().Centre().DoubleBorder());
 #else
@@ -339,13 +432,13 @@ void wxGenericColourDialog::InitializeColours(void)
                 }
             }
         }
-        m_colourData.m_dataColour.Set( curr.Red(), curr.Green(), curr.Blue() );
+        m_colourData.SetColour(curr);
     }
     else
     {
         m_whichKind = 1;
         m_colourSelection = 0;
-        m_colourData.m_dataColour.Set( 0, 0, 0 );
+        m_colourData.SetColour(wxColour(0, 0, 0));
     }
 }
 
@@ -371,28 +464,37 @@ void wxGenericColourDialog::PaintBasicColours(wxDC& dc)
     }
 }
 
-void wxGenericColourDialog::PaintCustomColours(wxDC& dc)
+#if !wxCLRDLGG_USE_PREVIEW_WITH_ALPHA
+void wxGenericColourDialog::PaintCustomColours(wxDC& dc, int clrIndex)
 {
-  int i;
-  for (i = 0; i < 2; i++)
-  {
-    int j;
-    for (j = 0; j < 8; j++)
+    int idxStart;
+    int idxEnd;
+    // For clrIndex == -1 redraw all custom colours
+    if ( clrIndex < 0 || clrIndex >= WXSIZEOF(m_customColours) )
     {
-      int ptr = i*8 + j;
-
-      int x = (j*(m_smallRectangleSize.x+m_gridSpacing)) + m_customColoursRect.x;
-      int y = (i*(m_smallRectangleSize.y+m_gridSpacing)) + m_customColoursRect.y;
-
-      dc.SetPen(*wxBLACK_PEN);
-
-      wxBrush brush(m_customColours[ptr]);
-      dc.SetBrush(brush);
-
-      dc.DrawRectangle( x, y, m_smallRectangleSize.x, m_smallRectangleSize.y);
+        idxStart = 0;
+        idxEnd = WXSIZEOF(m_customColours) - 1;
+    }
+    else
+    {
+        idxStart = clrIndex;
+        idxEnd = clrIndex;
+    }
+
+    for (int i = idxStart; i <= idxEnd; i++)
+    {
+        int x = ((i % 8)*(m_smallRectangleSize.x+m_gridSpacing)) + m_customColoursRect.x;
+        int y = ((i / 8)*(m_smallRectangleSize.y+m_gridSpacing)) + m_customColoursRect.y;
+
+        dc.SetPen(*wxBLACK_PEN);
+
+        wxBrush brush(m_customColours[i]);
+        dc.SetBrush(brush);
+
+        dc.DrawRectangle(x, y, m_smallRectangleSize.x, m_smallRectangleSize.y);
     }
-  }
 }
+#endif // !wxCLRDLGG_USE_PREVIEW_WITH_ALPHA
 
 void wxGenericColourDialog::PaintHighlight(wxDC& dc, bool draw)
 {
@@ -442,16 +544,24 @@ void wxGenericColourDialog::PaintHighlight(wxDC& dc, bool draw)
 
 void wxGenericColourDialog::PaintCustomColour(wxDC& dc)
 {
+#if wxCLRDLGG_USE_PREVIEW_WITH_ALPHA
+    wxUnusedVar(dc);
+
+    wxBitmap bmp(m_singleCustomColourRect.GetSize(), 32);
+    bmp.UseAlpha();
+    DoPreviewBitmap(bmp, m_colourData.GetColour());
+    m_customColourBmp->SetBitmap(bmp);
+#else
     dc.SetPen(*wxBLACK_PEN);
 
-    wxBrush *brush = new wxBrush(m_colourData.m_dataColour);
+    wxBrush *brush = new wxBrush(m_colourData.GetColour());
     dc.SetBrush(*brush);
 
-    dc.DrawRectangle( m_singleCustomColourRect.x, m_singleCustomColourRect.y,
-                      m_customRectangleSize.x, m_customRectangleSize.y);
+    dc.DrawRectangle(m_singleCustomColourRect);
 
     dc.SetBrush(wxNullBrush);
     delete brush;
+#endif // wxCLRDLGG_USE_PREVIEW_WITH_ALPHA/!wxCLRDLGG_USE_PREVIEW_WITH_ALPHA
 }
 
 void wxGenericColourDialog::OnBasicColourClick(int which)
@@ -466,11 +576,13 @@ void wxGenericColourDialog::OnBasicColourClick(int which)
     m_redSlider->SetValue( m_standardColours[m_colourSelection].Red() );
     m_greenSlider->SetValue( m_standardColours[m_colourSelection].Green() );
     m_blueSlider->SetValue( m_standardColours[m_colourSelection].Blue() );
+    if ( m_colourData.GetChooseAlpha() )
+    {
+        m_alphaSlider->SetValue( m_standardColours[m_colourSelection].Alpha() );
+    }
 #endif // wxUSE_SLIDER
 
-    m_colourData.m_dataColour.Set(m_standardColours[m_colourSelection].Red(),
-                                m_standardColours[m_colourSelection].Green(),
-                                m_standardColours[m_colourSelection].Blue());
+    m_colourData.SetColour(m_standardColours[m_colourSelection]);
 
     PaintCustomColour(dc);
     PaintHighlight(dc, true);
@@ -487,11 +599,13 @@ void wxGenericColourDialog::OnCustomColourClick(int which)
     m_redSlider->SetValue( m_customColours[m_colourSelection].Red() );
     m_greenSlider->SetValue( m_customColours[m_colourSelection].Green() );
     m_blueSlider->SetValue( m_customColours[m_colourSelection].Blue() );
+    if ( m_colourData.GetChooseAlpha() )
+    {
+        m_alphaSlider->SetValue( m_customColours[m_colourSelection].Alpha() );
+    }
 #endif // wxUSE_SLIDER
 
-    m_colourData.m_dataColour.Set(m_customColours[m_colourSelection].Red(),
-                                m_customColours[m_colourSelection].Green(),
-                                m_customColours[m_colourSelection].Blue());
+    m_colourData.SetColour(m_customColours[m_colourSelection]);
 
     PaintCustomColour(dc);
     PaintHighlight(dc, true);
@@ -521,13 +635,18 @@ void wxGenericColourDialog::OnAddCustom(wxCommandEvent& WXUNUSED(event))
     PaintHighlight(dc, true);
   }
 
-  m_customColours[m_colourSelection].Set(m_colourData.m_dataColour.Red(),
-                                     m_colourData.m_dataColour.Green(),
-                                     m_colourData.m_dataColour.Blue());
+  m_customColours[m_colourSelection] = m_colourData.GetColour();
 
   m_colourData.SetCustomColour(m_colourSelection, m_customColours[m_colourSelection]);
 
-  PaintCustomColours(dc);
+#if wxCLRDLGG_USE_PREVIEW_WITH_ALPHA
+    wxBitmap bmp(m_smallRectangleSize, 32);
+    bmp.UseAlpha();
+    DoPreviewBitmap(bmp, m_customColours[m_colourSelection]);
+    m_customColoursBmp[m_colourSelection]->SetBitmap(bmp);
+#else
+    PaintCustomColours(dc, m_colourSelection);
+#endif // wxCLRDLGG_USE_PREVIEW_WITH_ALPHA/!wxCLRDLGG_USE_PREVIEW_WITH_ALPHA
 }
 
 #if wxUSE_SLIDER
@@ -538,7 +657,8 @@ void wxGenericColourDialog::OnRedSlider(wxCommandEvent& WXUNUSED(event))
     return;
 
   wxClientDC dc(this);
-  m_colourData.m_dataColour.Set((unsigned char)m_redSlider->GetValue(), m_colourData.m_dataColour.Green(), m_colourData.m_dataColour.Blue());
+  wxColour c = m_colourData.GetColour();
+  m_colourData.SetColour(wxColour((unsigned char)m_redSlider->GetValue(), c.Green(), c.Blue(), c.Alpha()));
   PaintCustomColour(dc);
 }
 
@@ -548,7 +668,8 @@ void wxGenericColourDialog::OnGreenSlider(wxCommandEvent& WXUNUSED(event))
     return;
 
   wxClientDC dc(this);
-  m_colourData.m_dataColour.Set(m_colourData.m_dataColour.Red(), (unsigned char)m_greenSlider->GetValue(), m_colourData.m_dataColour.Blue());
+  wxColour c = m_colourData.GetColour();
+  m_colourData.SetColour(wxColour(c.Red(), (unsigned char)m_greenSlider->GetValue(), c.Blue(), c.Alpha()));
   PaintCustomColour(dc);
 }
 
@@ -558,10 +679,86 @@ void wxGenericColourDialog::OnBlueSlider(wxCommandEvent& WXUNUSED(event))
     return;
 
   wxClientDC dc(this);
-  m_colourData.m_dataColour.Set(m_colourData.m_dataColour.Red(), m_colourData.m_dataColour.Green(), (unsigned char)m_blueSlider->GetValue());
+  wxColour c = m_colourData.GetColour();
+  m_colourData.SetColour(wxColour(c.Red(), c.Green(), (unsigned char)m_blueSlider->GetValue(), c.Alpha()));
   PaintCustomColour(dc);
 }
 
+void wxGenericColourDialog::OnAlphaSlider(wxCommandEvent& WXUNUSED(event))
+{
+    wxColour c = m_colourData.GetColour();
+    m_colourData.SetColour(wxColour(c.Red(), c.Green(), c.Blue(), (unsigned char)m_alphaSlider->GetValue()));
+
+    wxClientDC dc(this);
+    PaintCustomColour(dc);
+}
+
 #endif // wxUSE_SLIDER
 
+#if wxCLRDLGG_USE_PREVIEW_WITH_ALPHA
+void wxGenericColourDialog::DoPreviewBitmap(wxBitmap& bmp, const wxColour& colour)
+{
+    if ( bmp.HasAlpha() && colour.Alpha() != wxALPHA_OPAQUE )
+    {
+        // For real ARGB draw a chessboard grid
+        // with actual ARGB fields and reference RGB fields.
+        const int w = bmp.GetWidth();
+        const int h = bmp.GetHeight();
+
+        // Calculate field size: 4 fields per row/column,
+        // with size in range [2..10]
+        int dx = wxMax(wxMin(w / 4, 10), 2);
+        int dy = wxMax(wxMin(h / 4, 10), 2);
+        // We want a square field
+        dx = wxMax(dx, dy);
+        dy = dx;
+
+        // Prepare opaque colour
+        wxColour colourRGB(colour.Red(), colour.Green(), colour.Blue(), wxALPHA_OPAQUE);
+
+        {
+            wxBrush brushARGB(colour);
+            wxBrush brushRGB(colourRGB);
+
+            wxMemoryDC mdc(bmp);
+            {
+                wxGCDC gdc(mdc);
+
+                gdc.SetPen(*wxTRANSPARENT_PEN);
+
+                for (int x = 0, ix = 0; x < w; x += dx, ix++)
+                {
+                    for (int y = 0, iy = 0; y < h; y += dy, iy++)
+                    {
+                        if ( (ix+iy) % 2 == 0 )
+                        {
+                            gdc.SetBrush(brushARGB);
+                        }
+                        else
+                        {
+                            gdc.SetBrush(brushRGB);
+                        }
+                        gdc.DrawRectangle(x, y, dx, dy);
+                    }
+                }
+
+                // Draw a frame
+                gdc.SetPen(*wxBLACK_PEN);
+                gdc.SetBrush(*wxTRANSPARENT_BRUSH);
+                gdc.DrawRectangle(0, 0, w, h);
+            }
+        }
+    }
+    else
+    {
+        wxMemoryDC mdc(bmp);
+        // Fill with custom colour
+        wxBrush brush(colour);
+        mdc.SetPen(*wxBLACK_PEN);
+        mdc.SetBrush(brush);
+        mdc.DrawRectangle(wxPoint(0, 0), bmp.GetSize());
+    }
+}
+#endif // wxCLRDLGG_USE_PREVIEW_WITH_ALPHA
+
 #endif // wxUSE_COLOURDLG