A supper simple GUI with only one push button doesn't work weirdly

I created a very simple GUI on MATLAB version R2015a. That program just only contains a push button like below figure:

When the button is hit, the callback "disp('Hello World')" will be executed. But when I run the GUI, nothing happens. Could some one help me? Below is the callback:

% --- Executes on button press in pushbutton1.
function pushbutton1_Callback(hObject, eventdata, handles)
% hObject    handle to pushbutton1 (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)

%surf(membrane(1))
disp('Hello World')
%guidata(hObject, handles);

Answer 1

[Image Analyst]

Set a breakpoint on the disp line to see if it gets there.

Are you sure you looked in the command window?

Instead of disp(), try this:

uiwait(helpdlg('Hello Chuong!'));

to put it in a popup message box instead of the command window.

Answer 2

[Chuong Le]

Dear Image Analyst,

I apply setting breakpoints to debug; but the GUI doesn't work. The callback might do nothing (disp line is not reached maybe).

I finally find the cause may come from insufficient software installation. Reinstalling to MATLAB version R2015b with full license settings solved this weird issue. Thank you.