I am writing my thesis and I face a problem with the appendices.
My code is below:
\documentclass[12pt]{book}
% package to activate greek language - the sequence languages appear below is IMPORTANT!!!
\usepackage[greek,english]{babel}
\usepackage{varioref}
%\usepackage{hyperref}
\usepackage{float}
\usepackage{multirow}
% package to handle graphics
\usepackage{graphicx}
\graphicspath{{images/}}
% package to handle multiple figures in a minipage
\usepackage{subfigure}
% package to extend math capabilities
\usepackage{amsmath,amssymb,isotope}
\usepackage[version=3]{mhchem}
%package to activate XeTeX font manager
\usepackage{fontspec}
\usepackage[titletoc]{appendix}
% DOCUMENT LAYOUT
\usepackage{geometry}
\geometry{a4paper, textwidth=5.5in, textheight=8.5in, headheight= 15pt, marginparsep=7pt, marginparwidth=.6in}
%\geometry{a4paper}
\setlength\parindent{8mm}
\setlength\parskip{5mm}
% FONTS
\usepackage{xunicode}
\usepackage{xltxtra}
\usepackage{xcolor}
\defaultfontfeatures{Mapping=tex-text} % converts LaTeX specials (``quotes'' --- dashes etc.) to unicode
%\setromanfont [Ligatures={Common}, BoldFont={GFS Artemisia Bold}, ItalicFont={Gentium Italic}]{Gentium}
%\setmonofont[Scale=0.8]{Monaco}
\setmainfont{Times New Roman} % You can set your main font here.
% ---- CUSTOM AMPERSAND
\newcommand{\amper}{{\fontspec[Scale=.95]{Gentium Italic}\selectfont\itshape\&}}
% package to handle line spacing
\usepackage{setspace}
% HEADINGS
\usepackage{sectsty}
\usepackage[normalem]{ulem}
\sectionfont{\rmfamily\mdseries\upshape\Large}
\subsectionfont{\rmfamily\bfseries\upshape\normalsize}
\subsubsectionfont{\rmfamily\mdseries\upshape\normalsize}
% PDF SETUP
% ---- FILL IN HERE THE DOC TITLE AND AUTHOR
\usepackage[unicode, driverfallback=dvipdfmx, bookmarks, colorlinks, breaklinks, pdftitle={Theo J. Mertzimekis - A thesis template for UoA students},pdfauthor={tmertzi}]{hyperref}
\hypersetup{linkcolor=blue,citecolor=blue,filecolor=black,urlcolor=blue}
% package for fancy style headers and footers
\usepackage{fancybox}
% redefine bullet symbols and section style
\renewcommand\thesection{\arabic{section}.}
\renewcommand{\labelitemi}{$\blacktriangleright$}
\renewcommand{\labelitemii}{$\bullet$}
\newcommand{\itemcheck}{\item[\checkmark]}
\newcommand{\itembullet}{\item[$\bullet$]}
\newcommand{\itemdiamond}{\item[$\diamond$]}
\newcommand{\itemtriangleright}{\item[$\triangleright$]}
\newcommand{\itemcirc}{\item[$\circ$]}
\newcommand{\itemsquare}{\item[$\square$]}
% change captions especially for greek language - if the document is in ENGLISH, they should vanish
\addto\captionsenglish{%
\renewcommand\prefacename{Πρόλογος}%
\renewcommand\refname{Αναφορές}%
\renewcommand\abstractname{Περίληψη}%
\renewcommand\bibname{Βιβλιογραφία}%
\renewcommand\chaptername{Κεφάλαιο}%
\renewcommand\appendixname{Παράρτημα}%
\renewcommand\contentsname{Περιεχόμενα}%
\renewcommand\listfigurename{Κατάλογος Σχημάτων}%
\renewcommand\listtablename{Κατάλογος Πινάκων}%
\renewcommand\indexname{Ευρετήριο}%
\renewcommand\figurename{Σχήμα}%
\renewcommand\tablename{Πίνακας}%
\renewcommand\partname{Μέρος}%
\renewcommand\enclname{Συνημμένα}%
\renewcommand\ccname{Κοινοποίηση}%
\renewcommand\headtoname{Προς}%
\renewcommand\pagename{Σελίδα}%
\renewcommand\seename{βλέπε}%
\renewcommand\alsoname{βλέπε επίσης}%
\renewcommand\proofname{Απόδειξη}%
\renewcommand\glossaryname{Γλωσσάρι}%
}
\usepackage{xgreek}
\usepackage{csquotes}
\usepackage[backref=true,backend=biber,style=authoryear]{biblatex}
\addbibresource{bibliography.bib}
\usepackage{fancyhdr}
\pagestyle{fancy}
\fancyhf{}
\fancyhead[LE,RO]{\leftmark}
\cfoot{\thepage}
\renewcommand{\chaptermark}[1]{\markboth{\MakeUppercase{#1}}{}}
\usepackage{afterpage}
\newcommand\blankpage{%
\null
\thispagestyle{empty}%
%\addtocounter{page}{-1}%
\newpage}
%%%%%%%%% END OF PREAMBLE %%%%%%%%%%%%
\begin{document}
\setlanguage{greek} %% this is to activate greek hyphenation
\chapter{Introduction}
\chapter{Related Work}
...
\begin{appendices}
\chapter{Μοντέλο}
\end{appendices}
\end{document}
The result is:
Does anyone know why this box is appeared next to letter A and how can I remove it?

xgreekand packageappendix. Without it I do not get your box (I get an apostroph instead your box). Can you explain me whatxgreekdoes for you? Why do you change the english words to be greek instead of using languagegreekas main language? Do you need english in your document or do you only use it in the bibliography? – Mensch Apr 02 '19 at 21:16