Added wxComboCtrlBase::m_hasTcBgCol. Re-using base wxWindow::m_hasBgCol was trouble.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@67256 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/combo.h

@@ -713,6 +713,9 @@ protected:
     // should the focus be reset to the textctrl in idle time?
     bool                    m_resetFocus;
 
+    // is the text-area background colour overridden?
+    bool                    m_hasTcBgCol;
+
 private:
     void Init();