hidden root works in wxGenericDirCtrl again

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@15066 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/generic/dirctrlg.h

@@ -157,8 +157,12 @@ public:
     // Resize the components of the control
     void DoResize();
     
+    // Collapse & expand the tree, thus re-creating it from scratch:
+    void ReCreateTree();
+    
 protected:
     void ExpandDir(wxTreeItemId parentId);
+    void CollapseDir(wxTreeItemId parentId);
     void AddSection(const wxString& path, const wxString& name, int imageId = 0);
     //void FindChildFiles(wxTreeItemId id, int dirFlags, wxArrayString& filenames);