Can suppress themed notebook page with wxNB_NOPAGETHEME or

setting system option msw.notebook.themed-background to 0


git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@31807 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/notebook.h

@@ -91,6 +91,9 @@ public:
     // implement some base class functions
     virtual wxSize CalcSizeFromPage(const wxSize& sizePage) const;
 
+    // On platforms that support it, get the theme page background colour, else invalid colour
+    virtual wxColour GetThemeBackgroundColour() const { return wxNullColour; }
+
 protected:
     DECLARE_NO_COPY_CLASS(wxNotebookBase)
 };