diff --git a/src/osx/carbon/region.cpp b/src/osx/carbon/region.cpp
index 7362c13aac..8f3eeb884f 100644
--- a/src/osx/carbon/region.cpp
+++ b/src/osx/carbon/region.cpp
@@ -202,17 +202,7 @@ bool wxRegion::DoCombine(const wxRegion& region, wxRegionOp op)
 {
     wxCHECK_MSG( region.IsOk(), false, wxT("invalid wxRegion") );
 
-    // Don't change shared data
-    if (!m_refData)
-    {
-        m_refData = new wxRegionRefData();
-    }
-    else if (m_refData->GetRefCount() > 1)
-    {
-        wxRegionRefData* ref = (wxRegionRefData*)m_refData;
-        UnRef();
-        m_refData = new wxRegionRefData(*ref);
-    }
+    AllocExclusive();
 
     switch (op)
     {