I have a menu window of a propietary uia application which raises a subwindow. This subwindow raises a system file dialog window. All three windows have a full tree information which I can display by dump_tree(). When the system file dialog window is closed (because the file is selected) and the focus is again in the subwindow the tree information is nearly empty (again checked by dump_tree()), only the stump with the subwindow without any control elements exists now. Descendants() has no result neither. Can I 'save' the tree information before it is deleted? As consecuence of the lost tree information the python application doesn't find any button and I cant control the propietary application any more.