fix wrong clear selection (modified patch 1763916)

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@48090 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/gtk/clipbrd.h

@@ -73,12 +73,19 @@ public:
     bool GTKOnTargetReceived(const wxDataFormat& format);
 
 private:
+    // the data object for the specific selection
+    wxDataObject *& Data(Kind kind)
+    {
+        return kind == Primary ? m_dataPrimary : m_dataClipboard;
+    }
+
     // the data object we're currently using
     wxDataObject *& Data()
     {
-        return m_usePrimary ? m_dataPrimary : m_dataClipboard;
+        return Data(m_usePrimary ? Primary : Clipboard);
     }
 
+
     // set or unset selection ownership
     bool SetSelectionOwner(bool set = true);