Fix copy to clipboard by flushing the updated data. (#1623)

src/osx/carbon/clipbrd.cpp

@@ -60,7 +60,11 @@ void wxClipboard::Clear()
 
 bool wxClipboard::Flush()
 {
-    return false;
+    wxCHECK_MSG( m_open, false, wxT("clipboard not open") );
+
+    wxOSXPasteboard::GetGeneralClipboard()->Flush();
+
+    return true;
 }
 
 bool wxClipboard::Open()
@@ -105,6 +109,8 @@ bool wxClipboard::AddData( wxDataObject *data )
 
     data->WriteToSink(wxOSXPasteboard::GetGeneralClipboard());
 
+    Flush();
+
     m_data = data;
 
     return true;