More comments about non-native GTH widgets.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@40890 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

docs/gtk/nonnative.txt

@@ -4,10 +4,17 @@ List of classes which should use their native GTK+ equivalents but don't:
     Problem with multiple fields, GtkStatusbar only seems to support one pane
 
 - wxTreeCtrl
+    Ryan Norton has implemented this
+    
 - wxListCtrl
     Could be reimplemeted in terms of wxDataViewCtrl?
 
 - wxSplitterWindow
+    Not possible because GTK's GtkHPane and GtkVPane
+    only support either horizontal or vertical panes
+    (therefore their names) whereas wxSplitterWindow
+    supports both and can even change orientiation at
+    runtime.
 
 - wxDatePickerCtrl
 - wxCalendarCtrl