diff --git a/src/wxmac/include/mac/wx_dccan.h b/src/wxmac/include/mac/wx_dccan.h
index 0a1abac7c1..772792aa4a 100644
--- a/src/wxmac/include/mac/wx_dccan.h
+++ b/src/wxmac/include/mac/wx_dccan.h
@@ -38,7 +38,7 @@ class wxCanvasDC: public wxbCanvasDC
   int pixmapWidth;
   int pixmapHeight;
 
-  RgnHandle current_reg, onpaint_reg;
+  RgnHandle current_reg, onpaint_reg, clip_reg;
 
   int current_pen_join;
   int current_pen_cap;
diff --git a/src/wxmac/src/mac/wx_canvs.cc b/src/wxmac/src/mac/wx_canvs.cc
index 302a946856..b5a7fe26ce 100644
--- a/src/wxmac/src/mac/wx_canvs.cc
+++ b/src/wxmac/src/mac/wx_canvs.cc
@@ -869,12 +869,20 @@ void wxCanvas::DoPaint(void)
       if (EmptyRgn(needs_update))
         return;
 
-      rgn = NewRgn();
+      if (cStyle & wxTRANSPARENT_WIN)
+        rgn = NewRgn();
+      else
+        rgn = NULL;
       if (rgn) {
         CopyRgn(needs_update, rgn);
         SetRectRgn(needs_update, 0, 0, 0, 0);
-        wx_dc->onpaint_reg = rgn;
+        if (wx_dc->clip_reg) {
+          /* FIXME: nested on-paint... */
+        }
+        wx_dc->clip_reg = rgn;
         wx_dc->SetCanvasClipping();
+      } else {
+        SetRectRgn(needs_update, 0, 0, 0, 0);
       }
     } else
       rgn = NULL;
@@ -886,20 +894,24 @@ void wxCanvas::DoPaint(void)
       RGBColor pixel;
       
       pixel = bgcol->pixel;
-
+      
       SetCurrentDC();
+      if (rgn)
+        SetClip(rgn);
       GetThemeDrawingState(&s);
       GetControlBounds(cPaintControl, &itemRect);
       RGBBackColor(&pixel);
       BackPat(GetWhitePattern());
       EraseRect(&itemRect);
       SetThemeDrawingState(s, TRUE);
+      if (rgn)
+        cMacDC->setCurrentUser(NULL);
     }
 
     OnPaint();
 
     if (rgn) {
-      wx_dc->onpaint_reg = NULL;
+      wx_dc->clip_reg = NULL;
       wx_dc->SetCanvasClipping();
       DisposeRgn(rgn);
     }
diff --git a/src/wxmac/src/mac/wx_dccan1.cc b/src/wxmac/src/mac/wx_dccan1.cc
index a61151013e..ce118dcfc5 100644
--- a/src/wxmac/src/mac/wx_dccan1.cc
+++ b/src/wxmac/src/mac/wx_dccan1.cc
@@ -70,8 +70,9 @@ void wxCanvasDC::Init(wxCanvas* the_canvas)
   pixmapWidth = 0;
   pixmapHeight = 0;
 
-  current_reg = NULL ;
-  onpaint_reg = NULL ;
+  current_reg = NULL;
+  onpaint_reg = NULL;
+  clip_reg = NULL;
 
   min_x = 0; min_y = 0; max_x = 0; max_y = 0;
 
@@ -135,6 +136,10 @@ wxCanvasDC::~wxCanvasDC(void)
     ::DisposeRgn(onpaint_reg);
     onpaint_reg = NULL;
   }
+  if (clip_reg) {
+    ::DisposeRgn(clip_reg);
+    clip_reg = NULL;
+  }
   canvas = NULL;
 
   if (reset_chain == this) {
@@ -279,7 +284,7 @@ void wxCanvasDC::SetCanvasClipping(void)
   if (current_reg) {
     ::DisposeRgn(current_reg);
   }
-  if (clipping || onpaint_reg) {
+  if (clipping || onpaint_reg || clip_reg) {
     current_reg = ::NewRgn();
     CheckMemOK(current_reg);
   } else
@@ -287,18 +292,22 @@ void wxCanvasDC::SetCanvasClipping(void)
   
   if (clipping && !clipping->rgn) {
     /* NULL rgn pointer means the empty region */
-    if (!current_reg) {
-      current_reg = ::NewRgn();
-      CheckMemOK(current_reg);
-    }
   } else if (clipping) {
     ::CopyRgn(clipping->rgn, current_reg);
     ::OffsetRgn(current_reg, auto_device_origin_x, auto_device_origin_y); 
     if (onpaint_reg) {
-      ::SectRgn(current_reg, onpaint_reg, current_reg) ;
+      ::SectRgn(current_reg, onpaint_reg, current_reg);
+    }
+    if (clip_reg) {
+      ::SectRgn(current_reg, clip_reg, current_reg);
     }
   } else if (onpaint_reg) {
     ::CopyRgn(onpaint_reg, current_reg);
+    if (clip_reg) {
+      ::SectRgn(current_reg, clip_reg, current_reg);
+    }
+  } else if (clip_reg) {
+    ::CopyRgn(clip_reg, current_reg);
   }
 
   theCurrentUser = cMacDC->currentUser();
@@ -956,11 +965,17 @@ CGContextRef wxCanvasDC::GetCG()
     /* Leave the region empty */
   } else {
     if (clipRgn) {
-      if (onpaint_reg) {
+      if (onpaint_reg || clip_reg) {
 	RgnHandle visRgn;
 	visRgn = NewRgn();
 	if (visRgn) {
-	  ::CopyRgn(onpaint_reg, clipRgn); // GetPortClipRegion(qdp, clipRgn);
+          if (onpaint_reg) {
+            ::CopyRgn(onpaint_reg, clipRgn);
+            if (clip_reg)
+              ::SectRgn(current_reg, clip_reg, current_reg);
+          } else {
+            ::CopyRgn(clip_reg, clipRgn);
+          }
 	  ::OffsetRgn(clipRgn, gdx, gdy);
 	  GetPortVisibleRegion(qdp, visRgn);
 	  SectRgn(clipRgn, visRgn, clipRgn);