You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: chebguiWindow.m
    path of file: ./repos/chebfun
    
    the code of the file until where you have to start completion: function varargout = chebguiWindow(varargin)
%CHEBGUIWINDOW   Driver file for Chebfun's CHEBGUI
%   This m-file populates and controls Chebfun's CHEBGUI.
%
% See also CHEBGUI.

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% DEVELOPER NOTE:
%  This method implements most callback method of CHEBGUI, i.e., methods that
%  get executed when the user interacts with the GUI figure. Man
    
function button_exportsoln_Callback(hObject, eventdata, handles)
% Create a CHEBGUIEXPORTER object of the correct type:
exporter = chebguiExporter.constructor(handles.guifile.type);
% Export the solution to the workspace
exporter.toWorkspaceSolutionOnly(handles);
end

function button_fontinc_Callback(hObject, eventdata, handles)
handles = chebguiController.changeFontsize(handles, 1);
guidata(hObject, handles);
end

function button_fontdec_Callback(hObject, eventdata, handles)
handles = chebguiController.changeFontsize(handles, -1);
guidata(hObject, handles);
end

function keypress(hObject, eventdata, handles)
newString = cellstr(get(hObject, 'String'));
newString = removeTabs(newString); % Remove tabs
set(hObject, 'String', newString);
handles = chebguiController.callbackBCs(handles,  newString, 'rbc');
handles.guifile.RBC = newString;
guidata(hObject, handles);
end