How to write data to listbox from another GUI

Hello, I would like to ask you for help. I have two GUIs. First one calling function from second one GUI and this function writes data to listbox (second gui). I know situation is little bit complicated. How I do that is outlined bellow. Problem is that the data are not writen to listbox after calling this function from first GUI. For data transfer between GUIs I use commands setappdata and getappdata. I dont know where is the problem because i have verified that the data has been transfered and I think the handle of the listbox is also right.

Important parts of program from second GUI

% --- Executes just before ReseltFigure is made visible.
function ReseltFigure_OpeningFcn(hObject, eventdata, handles, varargin)
% This function has no output args, see OutputFcn.
% hObject    handle to figure
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)
% varargin   command line arguments to ReseltFigure (see VARARGIN)

% Choose default command line output for ReseltFigure
handles.output = hObject;

setappdata(0,'hReseltGUI',gcf);
setappdata(gcf,'fhWriteData2listbox',@WriteData2listbox);
setappdata(gcf,'hListbox',handles.result_listbox);
% Update handles structure
guidata(hObject, handles);

The function which is placed in m-file of the second GUI.

function WriteData2listbox
figure(getappdata(0,'hReseltGUI'));
hReseltGUI=getappdata(0,'hReseltGUI');
hListbox=findobj(hReseltGUI,'type','listbox');
g=getappdata(gcf,'hListbox');
a=getappdata(0,'Data');
celldisp(a);
set(g,'String',a);

Calling the function which is covered above. This part of code is written in first GUI.

     ReseltFigure; # Calling second GUI
      setappdata(0,'Data',SelectedLines)
      hResultGUI=getappdata(0,'hReseltGUI');
      fhWriteData=getappdata(hResultGUI,'fhWriteData2listbox');
      feval(fhWriteData);

Thank you for all your advice Jirka