diff --git a/docs/changes.txt b/docs/changes.txt
index 1b8ee90d70..dc1d948b26 100644
--- a/docs/changes.txt
+++ b/docs/changes.txt
@@ -74,7 +74,6 @@ All:
 - Add support for loading dynamic lexer in wxStyledTextCtrl (New Pagodi).
 - Handle strings with embedded NULs in wxDataStream (Nitch).
 - Don't crash in wxTextFile::GetLastLine() if the file is empty (crohr).
-- Many fixes and improvements in Direct2D, Cairo, and GDI+ graphics renderers.
 
 All (GUI):
 
@@ -92,6 +91,8 @@ All (GUI):
 - Implement auto complete in generic wxSearchCtrl (Eric Jensen).
 - Fix preserving selection when changing selection mode in wxGrid (jonkraber).
 - Fix wxTextEntry::SetHint() with wxTE_PASSWORD in generic implementation.
+- Many fixes and improvements in Direct2D, Cairo, and GDI+ graphics renderers.
+- Fix and unify clipping region support for MSW and GTK+.
 
 wxGTK:
 
diff --git a/src/gtk/dc.cpp b/src/gtk/dc.cpp
index e87585b6d5..bef12a5081 100644
--- a/src/gtk/dc.cpp
+++ b/src/gtk/dc.cpp
@@ -398,11 +398,43 @@ wxGTKDCImpl::~wxGTKDCImpl()
 
 void wxGTKDCImpl::DoSetClippingRegion( wxCoord x, wxCoord y, wxCoord width, wxCoord height )
 {
-    m_clipping = TRUE;
-    m_clipX1 = x;
-    m_clipY1 = y;
-    m_clipX2 = x + width;
-    m_clipY2 = y + height;
+    wxASSERT_MSG( width >= 0 && height >= 0,
+                  "Clipping box size values cannot be negative" );
+
+    wxRect newRegion(x, y, width, height);
+
+    wxRect clipRegion;
+    if ( m_clipping )
+    {
+        // New clipping box is an intersection
+        // of required clipping box and the current one.
+        wxRect curRegion(m_clipX1, m_clipY1, m_clipX2 - m_clipX1, m_clipY2 - m_clipY1);
+        clipRegion = curRegion.Intersect(newRegion);
+    }
+    else
+    {
+        // Effective clipping box is an intersection
+        // of required clipping box and DC surface.
+        int dcWidth, dcHeight;
+        DoGetSize(&dcWidth, &dcHeight);
+        wxRect dcRect(DeviceToLogicalX(0), DeviceToLogicalY(0),
+                      DeviceToLogicalXRel(dcWidth), DeviceToLogicalYRel(dcHeight));
+        clipRegion = dcRect.Intersect(newRegion);
+
+        m_clipping = true;
+    }
+
+    if ( clipRegion.IsEmpty() )
+    {
+        m_clipX1 = m_clipY1 = m_clipX2 = m_clipY2 = 0;
+    }
+    else
+    {
+        m_clipX1 = clipRegion.GetLeftTop().x;
+        m_clipY1 = clipRegion.GetLeftTop().y;
+        m_clipX2 = clipRegion.GetBottomRight().x + 1;
+        m_clipY2 = clipRegion.GetBottomRight().y + 1;
+    }
 }
 
 // ---------------------------------------------------------------------------
diff --git a/src/gtk/dcclient.cpp b/src/gtk/dcclient.cpp
index f0cd8151ce..05ccdea82b 100644
--- a/src/gtk/dcclient.cpp
+++ b/src/gtk/dcclient.cpp
@@ -1918,7 +1918,8 @@ void wxWindowDCImpl::DoSetDeviceClippingRegion( const wxRegion &region  )
 
     wxCoord xx, yy, ww, hh;
     m_currentClippingRegion.GetBox( xx, yy, ww, hh );
-    wxGTKDCImpl::DoSetClippingRegion( xx, yy, ww, hh );
+    wxGTKDCImpl::DoSetClippingRegion(DeviceToLogicalX(xx), DeviceToLogicalY(yy),
+                                     DeviceToLogicalXRel(ww), DeviceToLogicalYRel(hh));
 
     GdkRegion* gdkRegion = m_currentClippingRegion.GetRegion();
     gdk_gc_set_clip_region(m_penGC,   gdkRegion);