Saving the zoom in plot

I have a GUI where i plot my signal, I import the signal with 'getappdata', apply filter to the signal and plot it.

function slider1_Callback(hObject, eventdata, handles)
% hObject    handle to slider1 (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)

% Hints: get(hObject,'Value') returns position of slider
%        get(hObject,'Min') and get(hObject,'Max') to determine range of slider

%get slider value for frequency
sliderValue = get(handles.slider1,'Value');
%set editbox value
 set(handles.edit1,'String',sliderValue)
 %get the signal to be filtered
 sig = getappdata(0,'signal');

%instantiate the filter class
 f = ltiFilter.PT1();
%set the frequcny
 f.fc = sliderValue;
%apply filter
 for i = 1: length(sig)
    updated(i).filter = f.eval(sig(i).signal,sig(i).signal(1));
 end
 for i = 1:length(sig)
     plot(sig(i).time,sig(i).signal,sig(i).time,updated(i).filter)
     hold on
 end 
 hold off
 legend('raw','filt');

This code works correctly, but the only problem is when i re-slide, it re-plots so i lose then zoom. and have to re zoom. So i retrieve the and restore the current zoom like this:

   % retrieve the current zoom
   tmp_xlim = get(handles.axes1, 'xlim');
   tmp_ylim = get(handles.axes1, 'ylim');

   for i = 1:length(sig)
       plot(sig(i).time,sig(i).signal,sig(i).time,updated(i).filter);
       hold on
   end 
   hold off
   legend('raw','filt');

   % restore the zoom properties
   set(handles.axes1, 'xlim', tmp_xlim);
   set(handles.axes1, 'ylim', tmp_ylim);

Now the graph doesn't plot at all. Have no idea why. Any suggestions will be helpful.