Latex - width of the colorbox

Look at the CV template's use of EducationEntry:

newcommand{EducationEntry}[4]{
  noindent textbf{#1} hfill                  % Study
  colorbox{Black}{%
    parbox{6em}{%
    hfillcolor{White}#2}} par                % Duration
  noindent textit{#3} par                    % School
  noindenthangindent=2emhangafter=0 small #4    % Description
  normalsize par}

This sets the coloured box to contain text that is 6em wide. If anything wider than that is supplied, then it will break like accordingly. In contrast, WorkEntry doesn't have this paragraph setting:

newcommand{WorkEntry}[4]{                     % Same as EducationEntry
  noindent textbf{#1} hfill                  % Jobname
  colorbox{Black}{color{White}#2} par        % Duration
  noindent textit{#3} par                    % Company
  noindenthangindent=2emhangafter=0 small #4    % Description
  normalsize par}

Without this parbox (of fixed width), the box should shape to the size of its contents. If you wish to have a fixed with, update WorkEntry accordingly to use a pre-specified width. Alternatively, just use EducationExperience for you work experience as in the original template.

Here's the template with some updates (both EducationEntry and WorkEntry now fits an 10em parbox):

%%% LaTeX Template: Curriculum Vitae
%%%
%%% Source: http://www.howtotex.com/
%%% Feel free to distribute this template, but please keep the referal to HowToTeX.com.
%%% Date: July 2011

%%% ------------------------------------------------------------
%%% BEGIN PREAMBLE
%%% ------------------------------------------------------------
documentclass[paper=a4,fontsize=11pt]{scrartcl}                % KOMA-article class

%usepackage[english]{babel}                                % English language/hyphenation
%usepackage[protrusion=true,expansion=true]{microtype}     % Better typography
usepackage{amsmath,amsfonts,amsthm}                    % Math packages
usepackage[pdftex]{graphicx}                               % Enable pdflatex
usepackage[svgnames]{xcolor}                           % Colors by their 'svgnames'
usepackage{geometry}
    textheight=700px                                   % Saving trees ;-) 
usepackage{url}                                        % Clickable URL's
usepackage{wrapfig}                                    % Wrap text along figures

frenchspacing                                  % Better looking spacings after periods
pagestyle{empty}                               % No pagenumbers/headers/footers
%usepackage{bbding}                                    % Symbols

%%% Custom sectioning (sectsty package)
%%% ------------------------------------------------------------
usepackage{sectsty}                            % Custom sectioning (see below)

sectionfont{%                                  % Change font of section command
    usefont{OT1}{phv}{b}{n}%                   % bch-b-n: CharterBT-Bold font
    sectionrule{0pt}{0pt}{-5pt}{3pt}
    }

%%% Macros
%%% ------------------------------------------------------------
newlength{spacebox}
settowidth{spacebox}{8888888888}              % Box to align text
newcommand{sepspace}{vspace*{1em}}           % Vertical space macro

newcommand{MyName}[1]{
        Huge usefont{OT1}{phv}{b}{n} hfill #1        % Name
        par normalsize normalfont}

newcommand{MySlogan}[1]{
        large usefont{OT1}{phv}{m}{n}hfill textit{#1} % Slogan (optional)
        par normalsize normalfont}

newcommand{NewPart}[1]{section*{uppercase{#1}}}

newcommand{PersonalEntry}[2]{
        noindenthangindent=2emhangafter=0        % Indentation
        parbox{spacebox}{                     % Box to align text
        textit{#1}}                                % Entry name (birth, address, etc.)
        hspace{1.5em} #2 par}                 % Entry value

newcommand{SkillsEntry}[2]{                       % Same as PersonalEntry
        noindenthangindent=2emhangafter=0        % Indentation
        parbox{spacebox}{                     % Box to align text
        textit{#1}}                                % Entry name (birth, address, etc.)
        hspace{1.5em} #2 par}                 % Entry value   

newcommand{EducationEntry}[4]{
        noindent textbf{#1} hfill                    % Study
        colorbox{Black}{%
            parbox{10em}{%
            hfillcolor{White}#2}} par                % Duration
        noindent textit{#3} par                  % School
        noindenthangindent=2emhangafter=0 small #4  % Description
        normalsize par}

newcommand{WorkEntry}[4]{                     % Same as EducationEntry
        noindent textbf{#1} hfill                    % Jobname
        colorbox{Black}{%
            parbox{10em}{%
            hfillcolor{White}#2}} par        % Duration
        noindent textit{#3} par                  % Company
        noindenthangindent=2emhangafter=0 small #4  % Description
        normalsize par}



%%% ------------------------------------------------------------
%%% BEGIN DOCUMENT
%%% ------------------------------------------------------------
begin{document}
begin{wrapfigure}{l}{0.5textwidth}
    vspace*{-2em}
        includegraphics[width=0.15textwidth]{photo}
end{wrapfigure}

MyName{Your Name}
MySlogan{Curriculum Vitae}

sepspace

%%% Personal details
%%% ------------------------------------------------------------
NewPart{Personal details}{}

PersonalEntry{Birth}{January 1, 1980} 
PersonalEntry{Address}{111 First St, New York}
PersonalEntry{Phone}{(123) 000-0000}
PersonalEntry{Mail}{url{[email protected]}}

%%% Education
%%% ------------------------------------------------------------
NewPart{Education}{} 

EducationEntry{MSc. Name of Education}{2010-2012}{Name of
  University}{Descriptive text goes here. In order to maintain a stylish look, try to fill this description with a few lines of text. Do the same for the other entries in the education section.}
sepspace

EducationEntry{BSc. Name of Education}{2007-2010}{Name of University}{Descriptive text goes here. In order to maintain a stylish look, try to fill this description with a few lines of text. Do the same for the other entries in the education section.}

%%% Work experience
%%% ------------------------------------------------------------
NewPart{Work experience}{}

EducationEntry{Job name}{March 2013 - Present}{Company Name inc., Full-time}{Job description goes here. To maintain a stylish look, try to fill this description with a few lines of text. Do the same for the other entries in this section.}
sepspace

EducationEntry{Job name}{2010-2011}{Company Name inc., Part-time}{Job description goes here. To maintain a stylish look, try to fill this description with a few lines of text. Do the same for the other entries in this section.}

%%% Skills
%%% ------------------------------------------------------------
NewPart{Skills}{}

SkillsEntry{Languages}{Dutch (mother tongue)}
SkillsEntry{}{English (fluent)}
SkillsEntry{}{German (fluent)} 

SkillsEntry{Software}{textsc{Matlab}, LaTeX, textsc{Ansys}, textsc{Comsol}}


%%% References
%%% ------------------------------------------------------------
NewPart{References}{}
Available upon request
end{document}

---

As per request, for an adaptation of SkillsEntry, use

newcommand{SkillsEntry}[2]{                       % Same as PersonalEntry
        noindenthangindent=dimexprspacebox+2emrelaxhangafter=1        % Indentation
        nullhspace*{2em}makebox[spacebox][l]{%                     % Box to align text
        textit{#1}}%                               % Entry name (birth, address, etc.)
        #2 par}                 % Entry value  

which allows you to use

%%% Skills
%%% ------------------------------------------------------------
NewPart{Skills}{}

SkillsEntry{Languages}{Dutch (mother tongue)}
SkillsEntry{}{English (fluent)}
SkillsEntry{}{German (fluent)} 

SkillsEntry{Software}{textsc{Matlab}, LaTeX, textsc{Ansys}, textsc{Comsol},
  and them a large amount of other, obscure languages including textsc{APL}}

that yields

Note that the second argument is set a little closer than in the original layout. I've used the provided spacebox measure. However, this can be changed, if needed. For example, use 1.2spacebox instead to obtain a more spacier view: