If you pass handles as input and also output, you don't need guidata
Use guidata only to store/retrieve the GUI's data.
function [handles, movie] = myFcn(CurFigHandle)
handles = guidata(CurFigHandle); %In this case, use guidata to retrieve handles, since it was not an input
movie = handles.movie;
function [handles, movie] = myFcn(handles)
movie = handles.movie;
%No guidata required, since handles was passed as the input.
In GUIDE, the handles is pretty much always passed as the 3rd input to a callback function, so no need to use guidata to "retrieve" handle. You do need to use guidata to "store" any changes to handles though.
function pushbutton_callback(hObject, events, handles)
movie = handles.movie;
handles.movie = movie(1:end-1); %Changes made!
guidata(hObject, handles); %save modified handles
