Matlab - Problemas con el uso de un slider

function varargout = zoom_grafica_caballero(varargin)

gui_Singleton = 1;

gui_State = struct('gui_Name',       mfilename, ...

                   'gui_Singleton',  gui_Singleton, ...

                   'gui_OpeningFcn', @zoom_grafica_caballero_OpeningFcn, ...

                   'gui_OutputFcn',  @zoom_grafica_caballero_OutputFcn, ...

                   'gui_LayoutFcn',  [] , ...

                   'gui_Callback',   []);

if nargin && ischar(varargin{1})

    gui_State.gui_Callback = str2func(varargin{1});

end

if nargout

    [varargout{1:nargout}] = gui_mainfcn(gui_State, varargin{:});

else

    gui_mainfcn(gui_State, varargin{:});

end

function zoom_grafica_caballero_OpeningFcn(hObject, ~, handles, varargin)

handles.output = hObject;

guidata(hObject, handles);

function varargout = zoom_grafica_caballero_OutputFcn(~, ~, handles)

varargout{1} = handles.output;

function graficar_Callback(~, ~, ~)

x=linspace(-2*pi,2*pi);

plot(x,sin(x))

grid

h = zoom;

set(h,'Enable','on');