use custom selection colours in wxHtmlListBox again (restores functionality broken by patch 1650804 in r44640)

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@52264 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/htmllbox.h

@@ -111,8 +111,11 @@ protected:
     virtual void OnDrawItem(wxDC& dc, const wxRect& rect, size_t n) const;
     virtual wxCoord OnMeasureItem(size_t n) const;
 
-    // This method may be overriden to handle clicking on a link in
-    // the listbox. By default, clicking links is ignored.
+    // override this one to draw custom background for selected items correctly
+    virtual void OnDrawBackground(wxDC& dc, const wxRect& rect, size_t n) const;
+
+    // this method may be overridden to handle clicking on a link in the
+    // listbox (by default, clicks on links are simply ignored)
     virtual void OnLinkClicked(size_t n, const wxHtmlLinkInfo& link);
 
     // event handlers

include/wx/vlbox.h

@@ -269,6 +269,14 @@ protected:
     // common part of keyboard and mouse handling processing code
     void DoHandleItemClick(int item, int flags);
 
+    // paint the background of the given item using the provided colour if it's
+    // valid, otherwise just return false and do nothing (this is used by
+    // OnDrawBackground())
+    bool DoDrawSolidBackground(const wxColour& col,
+                               wxDC& dc,
+                               const wxRect& rect,
+                               size_t n) const;
+
 private:
     // the current item or wxNOT_FOUND
     //