diff --git a/include/wx/aui/tabart.h b/include/wx/aui/tabart.h
index 12621771a6..4a449678ac 100644
--- a/include/wx/aui/tabart.h
+++ b/include/wx/aui/tabart.h
@@ -103,6 +103,9 @@ public:
     virtual int GetBorderWidth(
                          wxWindow* wnd) = 0;
 
+    virtual int GetAdditionalBorderSpace(
+                         wxWindow* wnd) = 0;
+
     virtual int GetBestTabCtrlSize(
                          wxWindow* wnd,
                          const wxAuiNotebookPageArray& pages,
@@ -162,6 +165,9 @@ public:
     int GetBorderWidth(
                  wxWindow* wnd);
 
+    int GetAdditionalBorderSpace(
+                 wxWindow* wnd);
+
     wxSize GetTabSize(
                  wxDC& dc,
                  wxWindow* wnd,
@@ -258,6 +264,9 @@ public:
     int GetBorderWidth(
                  wxWindow* wnd);
 
+    int GetAdditionalBorderSpace(
+                 wxWindow* wnd);
+
     wxSize GetTabSize(
                  wxDC& dc,
                  wxWindow* wnd,
diff --git a/include/wx/aui/tabartgtk.h b/include/wx/aui/tabartgtk.h
index b094082d81..37b8587f1c 100644
--- a/include/wx/aui/tabartgtk.h
+++ b/include/wx/aui/tabartgtk.h
@@ -48,6 +48,7 @@ public:
     int GetBestTabCtrlSize(wxWindow* wnd, const wxAuiNotebookPageArray& pages,
                             const wxSize& required_bmp_size);
     int GetBorderWidth(wxWindow* wnd);
+    int GetAdditionalBorderSpace(wxWindow* wnd);
     virtual wxSize GetTabSize(wxDC& dc, wxWindow* wnd, const wxString& caption,
                               const wxBitmap& bitmap, bool active,
                               int close_button_state, int* x_extent);
diff --git a/src/aui/auibook.cpp b/src/aui/auibook.cpp
index 402724309b..30691c1c03 100644
--- a/src/aui/auibook.cpp
+++ b/src/aui/auibook.cpp
@@ -1544,9 +1544,9 @@ public:
         for (i = 0; i < page_count; ++i)
         {
             wxAuiNotebookPage& page = pages.Item(i);
-            int border_width = m_tabs->GetArtProvider()->GetBorderWidth(page.window);
+            int border_space = m_tabs->GetArtProvider()->GetAdditionalBorderSpace(page.window);
 
-            int height = m_rect.height - m_tabCtrlHeight - border_width;
+            int height = m_rect.height - m_tabCtrlHeight - border_space;
             if ( height < 0 )
             {
                 // avoid passing negative height to wxWindow::SetSize(), this
@@ -1556,16 +1556,16 @@ public:
 
             if (m_tabs->GetFlags() & wxAUI_NB_BOTTOM)
             {
-                page.window->SetSize(m_rect.x + 2 * border_width,
-                                     m_rect.y + 2 *  border_width,
-                                     m_rect.width - 4 * border_width,
+                page.window->SetSize(m_rect.x + border_space,
+                                     m_rect.y + border_space,
+                                     m_rect.width - 2 * border_space,
                                      height);
             }
             else //TODO: if (GetFlags() & wxAUI_NB_TOP)
             {
-                page.window->SetSize(m_rect.x + 2 * border_width,
+                page.window->SetSize(m_rect.x + border_space,
                                      m_rect.y + m_tabCtrlHeight,
-                                     m_rect.width - 4 * border_width,
+                                     m_rect.width - 2 * border_space,
                                      height);
             }
             // TODO: else if (GetFlags() & wxAUI_NB_LEFT){}
diff --git a/src/aui/tabart.cpp b/src/aui/tabart.cpp
index 62c6c5f9dd..9a30baf76c 100644
--- a/src/aui/tabart.cpp
+++ b/src/aui/tabart.cpp
@@ -610,6 +610,11 @@ int wxAuiGenericTabArt::GetBorderWidth(wxWindow* wnd)
     return 1;
 }
 
+int wxAuiGenericTabArt::GetAdditionalBorderSpace(wxWindow* WXUNUSED(wnd))
+{
+    return 0;
+}
+
 wxSize wxAuiGenericTabArt::GetTabSize(wxDC& dc,
                                       wxWindow* WXUNUSED(wnd),
                                       const wxString& caption,
@@ -1137,6 +1142,11 @@ int wxAuiSimpleTabArt::GetBorderWidth(wxWindow* wnd)
     return 1;
 }
 
+int wxAuiSimpleTabArt::GetAdditionalBorderSpace(wxWindow* WXUNUSED(wnd))
+{
+    return 0;
+}
+
 wxSize wxAuiSimpleTabArt::GetTabSize(wxDC& dc,
                                      wxWindow* WXUNUSED(wnd),
                                      const wxString& caption,
diff --git a/src/aui/tabartgtk.cpp b/src/aui/tabartgtk.cpp
index 28bfaa6aaf..e57ca3dd3f 100644
--- a/src/aui/tabartgtk.cpp
+++ b/src/aui/tabartgtk.cpp
@@ -487,6 +487,11 @@ int wxAuiGtkTabArt::GetBorderWidth(wxWindow* wnd)
                                                            GTK_NOTEBOOK (wxGTKPrivate::GetNotebookWidget())->tab_vborder);
 }
 
+int wxAuiGtkTabArt::GetAdditionalBorderSpace(wxWindow* wnd)
+{
+    return 2 * GetBorderWidth(wnd);
+}
+
 wxSize wxAuiGtkTabArt::GetTabSize(wxDC& dc,
                               wxWindow* wnd,
                               const wxString& caption,