diff --git a/webapp/components/code_preview.jsx b/webapp/components/code_preview.jsx
new file mode 100644
index 0000000000..8d2bc62693
--- /dev/null
+++ b/webapp/components/code_preview.jsx
@@ -0,0 +1,101 @@
+// Copyright (c) 2016 Mattermost, Inc. All Rights Reserved.
+// See License.txt for license information.
+
+import $ from 'jquery';
+import * as syntaxHightlighting from 'utils/syntax_hightlighting.jsx';
+import Constants from 'utils/constants.jsx';
+import FileInfoPreview from './file_info_preview.jsx';
+
+import React from 'react';
+
+export default class CodePreview extends React.Component {
+    constructor(props) {
+        super(props);
+
+        this.updateStateFromProps = this.updateStateFromProps.bind(this);
+        this.handleReceivedError = this.handleReceivedError.bind(this);
+        this.handleReceivedCode = this.handleReceivedCode.bind(this);
+
+        this.state = {
+            code: '',
+            lang: '',
+            loading: true,
+            success: true
+        };
+    }
+
+    componentDidMount() {
+        this.updateStateFromProps(this.props);
+    }
+
+    componentWillReceiveProps(nextProps) {
+        if (this.props.fileUrl !== nextProps.fileUrl) {
+            this.updateStateFromProps(nextProps);
+        }
+    }
+
+    updateStateFromProps(props) {
+        var usedLanguage = syntaxHightlighting.getLang(props.filename);
+
+        if (!usedLanguage || props.fileInfo.size > Constants.CODE_PREVIEW_MAX_FILE_SIZE) {
+            this.setState({code: '', lang: '', loading: false, success: false});
+            return;
+        }
+
+        this.setState({code: '', lang: usedLanguage, loading: true});
+
+        $.ajax({
+            async: true,
+            url: props.fileUrl,
+            type: 'GET',
+            error: this.handleReceivedError,
+            success: this.handleReceivedCode
+        });
+    }
+
+    handleReceivedCode(data) {
+	const parsed = syntaxHightlighting.formatCode(this.state.lang, data, this.props.filename)
+        this.setState({code: parsed, loading: false, success: true});
+    }
+
+    handleReceivedError() {
+        this.setState({loading: false, success: false});
+    }
+
+    static support(filename) {
+        return typeof syntaxHightlighting.getLang(filename) !== 'undefined';
+    }
+
+    render() {
+        if (this.state.loading) {
+            return (
+                <div className='view-image__loading'>
+                    <img
+                        className='loader-image'
+                        src='/static/images/load.gif'
+                    />
+                </div>
+            );
+        }
+
+        if (!this.state.success) {
+            return (
+                <FileInfoPreview
+                    filename={this.props.filename}
+                    fileUrl={this.props.fileUrl}
+                    fileInfo={this.props.fileInfo}
+                    formatMessage={this.props.formatMessage}
+                />
+            );
+        }
+
+        return <div dangerouslySetInnerHTML={{__html: this.state.code}}/>;
+    }
+}
+
+CodePreview.propTypes = {
+    filename: React.PropTypes.string.isRequired,
+    fileUrl: React.PropTypes.string.isRequired,
+    fileInfo: React.PropTypes.object.isRequired,
+    formatMessage: React.PropTypes.func.isRequired
+};
diff --git a/webapp/components/view_image.jsx b/webapp/components/view_image.jsx
index 2b7e033827..7572f88ae0 100644
--- a/webapp/components/view_image.jsx
+++ b/webapp/components/view_image.jsx
@@ -7,6 +7,7 @@ import * as Client from 'utils/client.jsx';
 import * as Utils from 'utils/utils.jsx';
 import AudioVideoPreview from './audio_video_preview.jsx';
 import Constants from 'utils/constants.jsx';
+import CodePreview from './code_preview.jsx';
 import FileInfoPreview from './file_info_preview.jsx';
 import FileStore from 'stores/file_store.jsx';
 import ViewImagePopoverBar from './view_image_popover_bar.jsx';
@@ -254,6 +255,15 @@ class ViewImageModal extends React.Component {
                         formatMessage={this.props.intl.formatMessage}
                     />
                 );
+            } else if (CodePreview.support(filename)) {
+                content = (
+                    <CodePreview
+                        filename={filename}
+                        fileUrl={fileUrl}
+                        fileInfo={fileInfo}
+                        formatMessage={this.props.intl.formatMessage}
+                    />
+                );
             } else {
                 content = (
                     <FileInfoPreview
@@ -323,6 +333,7 @@ class ViewImageModal extends React.Component {
                         onClick={this.props.onModalDismissed}
                     >
                         <div
+                            className='modal-back'
                             onMouseEnter={this.onMouseEnterImage}
                             onMouseLeave={this.onMouseLeaveImage}
                             onClick={(e) => e.stopPropagation()}
diff --git a/webapp/sass/components/_files.scss b/webapp/sass/components/_files.scss
index b854312c13..5522c6db8e 100644
--- a/webapp/sass/components/_files.scss
+++ b/webapp/sass/components/_files.scss
@@ -234,6 +234,7 @@
 
 .file-details__container {
     @include display-flex;
+    background: $white;
 
     .file-details {
         height: 270px;
diff --git a/webapp/sass/components/_modal.scss b/webapp/sass/components/_modal.scss
index 601aa33ab3..94378aabe3 100644
--- a/webapp/sass/components/_modal.scss
+++ b/webapp/sass/components/_modal.scss
@@ -256,13 +256,27 @@
             }
 
             > div {
-                background: $white;
                 display: inline-block;
                 min-height: 100px;
                 min-width: 320px;
                 position: relative;
             }
 
+            code {
+                min-height: 130px;
+                min-width: 330px;
+            }
+
+            pre, code {
+                display: inline-block;
+            }
+
+            .post-body--code {
+                max-height: calc(100vh - 80px);
+                max-width: calc(100vw - 80px);
+                overflow: auto;
+            }
+
             img {
                 max-height: 100%;
                 max-width: 100%;
diff --git a/webapp/sass/layout/_markdown.scss b/webapp/sass/layout/_markdown.scss
index e2180c64d9..b9acd8b5bf 100644
--- a/webapp/sass/layout/_markdown.scss
+++ b/webapp/sass/layout/_markdown.scss
@@ -22,29 +22,63 @@
 }
 
 .post-body--code {
+    overflow-x: auto;
+    overflow-y: hidden;
     position: relative;
 
     pre {
-        margin-bottom: 0;
-        overflow: auto;
-        word-break: normal;
-        word-wrap: normal;
+        border: 1px solid rgba(221,221,221,0.2);
+        border-radius: .25em;
+        margin: 0;
+        padding: 0px;
+        text-align: left;
+        white-space: nowrap;
+    }
+
+    code {
+        border: none;
+        white-space: pre;
+    }
+
+    td {
+        padding: 0 .5em;
+        vertical-align: top;
+    }
+
+    &:hover .post-body--code__language {
+        @include opacity(1);
     }
 }
 
 .post-body--code__language {
+    @include opacity(0);
     @include translate3d(0, 0, 0);
     background: #21586d;
+    border-radius: 0 .25em;
     color: $white;
-    font-size: 13px;
-    opacity: .7;
     padding: 4px 10px 5px;
     position: absolute;
     right: 0;
     top: 0;
+    -webkit-transition: opacity 0.6s;
+    -moz-transition: opacity 0.6s;
+    -o-transition: opacity 0.6s;
+    transition: opacity 0.6s;
     z-index: 5;
 }
 
+.post-body--code__lineno {
+    border-right: 1px solid #aaa;
+    color: #aaa;
+    margin-right: .5em;
+    text-align: right;
+    -webkit-user-select: none;
+    -moz-user-select: none;
+    -ms-user-select: none;
+    -o-user-select: none;
+    user-select: none;
+}
+
 .post__body {
     hr {
         @include opacity(.2);
@@ -108,9 +142,9 @@ blockquote {
 }
 
 pre {
-    border: none;
     color: inherit;
     margin: 5px 0;
+    padding: 0;
 }
 
 code {
diff --git a/webapp/utils/constants.jsx b/webapp/utils/constants.jsx
index c1e5277021..29178aca63 100644
--- a/webapp/utils/constants.jsx
+++ b/webapp/utils/constants.jsx
@@ -144,7 +144,7 @@ export default {
     PRESENTATION_TYPES: ['ppt', 'pptx'],
     SPREADSHEET_TYPES: ['xlsx', 'csv'],
     WORD_TYPES: ['doc', 'docx'],
-    CODE_TYPES: ['css', 'html', 'js', 'php', 'rb'],
+    CODE_TYPES: ['as', 'applescript', 'osascript', 'scpt', 'bash', 'sh', 'zsh', 'clj', 'boot', 'cl2', 'cljc', 'cljs', 'cljs.hl', 'cljscm', 'cljx', 'hic', 'coffee', '_coffee', 'cake', 'cjsx', 'cson', 'iced', 'cpp', 'c', 'cc', 'h', 'c++', 'h++', 'hpp', 'cs', 'csharp', 'css', 'd', 'di', 'dart', 'delphi', 'dpr', 'dfm', 'pas', 'pascal', 'freepascal', 'lazarus', 'lpr', 'lfm', 'diff', 'django', 'jinja', 'dockerfile', 'docker', 'erl', 'f90', 'f95', 'fsharp', 'fs', 'gcode', 'nc', 'go', 'groovy', 'handlebars', 'hbs', 'html.hbs', 'html.handlebars', 'hs', 'hx', 'java', 'jsp', 'js', 'jsx', 'json', 'jl', 'kt', 'ktm', 'kts', 'less', 'lisp', 'lua', 'mk', 'mak', 'md', 'mkdown', 'mkd', 'matlab', 'm', 'mm', 'objc', 'obj-c', 'ml', 'perl', 'pl', 'php', 'php3', 'php4', 'php5', 'php6', 'ps', 'ps1', 'pp', 'py', 'gyp', 'r', 'ruby', 'rb', 'gemspec', 'podspec', 'thor', 'irb', 'rs', 'scala', 'scm', 'sld', 'scss', 'st', 'sql', 'swift', 'tex', 'vbnet', 'vb', 'bas', 'vbs', 'v', 'veo', 'xml', 'html', 'xhtml', 'rss', 'atom', 'xsl', 'plist', 'yaml'],
     PDF_TYPES: ['pdf'],
     PATCH_TYPES: ['patch'],
     ICON_FROM_TYPE: {
@@ -514,30 +514,64 @@ export default {
         SPACE: 32,
         TAB: 9
     },
+    CODE_PREVIEW_MAX_FILE_SIZE: 500000, // 500 KB
     HighlightedLanguages: {
-        diff: 'Diff',
-        apache: 'Apache',
-        makefile: 'Makefile',
-        http: 'HTTP',
-        json: 'JSON',
-        markdown: 'Markdown',
-        javascript: 'JavaScript',
-        css: 'CSS',
-        nginx: 'nginx',
-        objectivec: 'Objective-C',
-        python: 'Python',
-        xml: 'XML',
-        perl: 'Perl',
-        bash: 'Bash',
-        php: 'PHP',
-        coffeescript: 'CoffeeScript',
-        cs: 'C#',
-        cpp: 'C++',
-        sql: 'SQL',
-        go: 'Go',
-        ruby: 'Ruby',
-        java: 'Java',
-        ini: 'ini'
+        actionscript: {name: 'ActionScript', extensions: ['as']},
+        applescript: {name: 'AppleScript', extensions: ['applescript', 'osascript', 'scpt']},
+        bash: {name: 'Bash', extensions: ['bash', 'sh', 'zsh']},
+        clojure: {name: 'Clojure', extensions: ['clj', 'boot', 'cl2', 'cljc', 'cljs', 'cljs.hl', 'cljscm', 'cljx', 'hic']},
+        coffeescript: {name: 'CoffeeScript', extensions: ['coffee', '_coffee', 'cake', 'cjsx', 'cson', 'iced']},
+        cpp: {name: 'C/C++', extensions: ['cpp', 'c', 'cc', 'h', 'c++', 'h++', 'hpp']},
+        cs: {name: 'C#', extensions: ['cs', 'csharp']},
+        css: {name: 'CSS', extensions: ['css']},
+        d: {name: 'D', extensions: ['d', 'di']},
+        dart: {name: 'Dart', extensions: ['dart']},
+        delphi: {name: 'Delphi', extensions: ['delphi', 'dpr', 'dfm', 'pas', 'pascal', 'freepascal', 'lazarus', 'lpr', 'lfm']},
+        diff: {name: 'Diff', extensions: ['diff', 'patch']},
+        django: {name: 'Django', extensions: ['django', 'jinja']},
+        dockerfile: {name: 'Dockerfile', extensions: ['dockerfile', 'docker']},
+        erlang: {name: 'Erlang', extensions: ['erl']},
+        fortran: {name: 'Fortran', extensions: ['f90', 'f95']},
+        fsharp: {name: 'F#', extensions: ['fsharp', 'fs']},
+        gcode: {name: 'G-Code', extensions: ['gcode', 'nc']},
+        go: {name: 'Go', extensions: ['go']},
+        groovy: {name: 'Groovy', extensions: ['groovy']},
+        handlebars: {name: 'Handlebars', extensions: ['handlebars', 'hbs', 'html.hbs', 'html.handlebars']},
+        haskell: {name: 'Haskell', extensions: ['hs']},
+        haxe: {name: 'Haxe', extensions: ['hx']},
+        java: {name: 'Java', extensions: ['java', 'jsp']},
+        javascript: {name: 'JavaScript', extensions: ['js', 'jsx']},
+        json: {name: 'JSON', extensions: ['json']},
+        julia: {name: 'Julia', extensions: ['jl']},
+        kotlin: {name: 'Kotlin', extensions: ['kt', 'ktm', 'kts']},
+        less: {name: 'Less', extensions: ['less']},
+        lisp: {name: 'Lisp', extensions: ['lisp']},
+        lua: {name: 'Lua', extensions: ['lua']},
+        makefile: {name: 'Makefile', extensions: ['mk', 'mak']},
+        markdown: {name: 'Markdown', extensions: ['md', 'mkdown', 'mkd']},
+        matlab: {name: 'Matlab', extensions: ['matlab', 'm']},
+        objectivec: {name: 'Objective C', extensions: ['mm', 'objc', 'obj-c']},
+        ocaml: {name: 'OCaml', extensions: ['ml']},
+        perl: {name: 'Perl', extensions: ['perl', 'pl']},
+        php: {name: 'PHP', extensions: ['php', 'php3', 'php4', 'php5', 'php6']},
+        powershell: {name: 'PowerShell', extensions: ['ps', 'ps1']},
+        puppet: {name: 'Puppet', extensions: ['pp']},
+        python: {name: 'Python', extensions: ['py', 'gyp']},
+        r: {name: 'R', extensions: ['r']},
+        ruby: {name: 'Ruby', extensions: ['ruby', 'rb', 'gemspec', 'podspec', 'thor', 'irb']},
+        rust: {name: 'Rust', extensions: ['rs']},
+        scala: {name: 'Scala', extensions: ['scala']},
+        scheme: {name: 'Scheme', extensions: ['scm', 'sld']},
+        scss: {name: 'SCSS', extensions: ['scss']},
+        smalltalk: {name: 'Smalltalk', extensions: ['st']},
+        sql: {name: 'SQL', extensions: ['sql']},
+        swift: {name: 'Swift', extensions: ['swift']},
+        tex: {name: 'TeX', extensions: ['tex']},
+        vbnet: {name: 'VB.Net', extensions: ['vbnet', 'vb', 'bas']},
+        vbscript: {name: 'VBScript', extensions: ['vbs']},
+        verilog: {name: 'Verilog', extensions: ['v', 'veo']},
+        xml: {name: 'HTML, XML', extensions: ['xml', 'html', 'xhtml', 'rss', 'atom', 'xsl', 'plist']},
+        yaml: {name: 'YAML', extensions: ['yaml']}
     },
     PostsViewJumpTypes: {
         BOTTOM: 1,
diff --git a/webapp/utils/markdown.jsx b/webapp/utils/markdown.jsx
index 635a392901..ee63e6a194 100644
--- a/webapp/utils/markdown.jsx
+++ b/webapp/utils/markdown.jsx
@@ -1,57 +1,9 @@
 // Copyright (c) 2015 Mattermost, Inc. All Rights Reserved.
 // See License.txt for license information.
 
-import highlightJs from 'highlight.js/lib/highlight.js';
-import highlightJsDiff from 'highlight.js/lib/languages/diff.js';
-import highlightJsApache from 'highlight.js/lib/languages/apache.js';
-import highlightJsMakefile from 'highlight.js/lib/languages/makefile.js';
-import highlightJsHttp from 'highlight.js/lib/languages/http.js';
-import highlightJsJson from 'highlight.js/lib/languages/json.js';
-import highlightJsMarkdown from 'highlight.js/lib/languages/markdown.js';
-import highlightJsJavascript from 'highlight.js/lib/languages/javascript.js';
-import highlightJsCss from 'highlight.js/lib/languages/css.js';
-import highlightJsNginx from 'highlight.js/lib/languages/nginx.js';
-import highlightJsObjectivec from 'highlight.js/lib/languages/objectivec.js';
-import highlightJsPython from 'highlight.js/lib/languages/python.js';
-import highlightJsXml from 'highlight.js/lib/languages/xml.js';
-import highlightJsPerl from 'highlight.js/lib/languages/perl.js';
-import highlightJsBash from 'highlight.js/lib/languages/bash.js';
-import highlightJsPhp from 'highlight.js/lib/languages/php.js';
-import highlightJsCoffeescript from 'highlight.js/lib/languages/coffeescript.js';
-import highlightJsCs from 'highlight.js/lib/languages/cs.js';
-import highlightJsCpp from 'highlight.js/lib/languages/cpp.js';
-import highlightJsSql from 'highlight.js/lib/languages/sql.js';
-import highlightJsGo from 'highlight.js/lib/languages/go.js';
-import highlightJsRuby from 'highlight.js/lib/languages/ruby.js';
-import highlightJsJava from 'highlight.js/lib/languages/java.js';
-import highlightJsIni from 'highlight.js/lib/languages/ini.js';
-
-highlightJs.registerLanguage('diff', highlightJsDiff);
-highlightJs.registerLanguage('apache', highlightJsApache);
-highlightJs.registerLanguage('makefile', highlightJsMakefile);
-highlightJs.registerLanguage('http', highlightJsHttp);
-highlightJs.registerLanguage('json', highlightJsJson);
-highlightJs.registerLanguage('markdown', highlightJsMarkdown);
-highlightJs.registerLanguage('javascript', highlightJsJavascript);
-highlightJs.registerLanguage('css', highlightJsCss);
-highlightJs.registerLanguage('nginx', highlightJsNginx);
-highlightJs.registerLanguage('objectivec', highlightJsObjectivec);
-highlightJs.registerLanguage('python', highlightJsPython);
-highlightJs.registerLanguage('xml', highlightJsXml);
-highlightJs.registerLanguage('perl', highlightJsPerl);
-highlightJs.registerLanguage('bash', highlightJsBash);
-highlightJs.registerLanguage('php', highlightJsPhp);
-highlightJs.registerLanguage('coffeescript', highlightJsCoffeescript);
-highlightJs.registerLanguage('cs', highlightJsCs);
-highlightJs.registerLanguage('cpp', highlightJsCpp);
-highlightJs.registerLanguage('sql', highlightJsSql);
-highlightJs.registerLanguage('go', highlightJsGo);
-highlightJs.registerLanguage('ruby', highlightJsRuby);
-highlightJs.registerLanguage('java', highlightJsJava);
-highlightJs.registerLanguage('ini', highlightJsIni);
-
 import * as TextFormatting from './text_formatting.jsx';
 import * as Utils from './utils.jsx';
+import * as syntaxHightlighting from './syntax_hightlighting.jsx';
 
 import marked from 'marked';
 import katex from 'katex';
@@ -110,31 +62,11 @@ class MattermostMarkdownRenderer extends marked.Renderer {
         this.formattingOptions = formattingOptions;
     }
 
-    code(code, language, escaped) {
+    code(code, language) {
         let usedLanguage = language || '';
         usedLanguage = usedLanguage.toLowerCase();
 
-        // treat html as xml to prevent injection attacks
-        if (usedLanguage === 'html') {
-            usedLanguage = 'xml';
-        }
-
-        if (HighlightedLanguages[usedLanguage]) {
-            const parsed = highlightJs.highlight(usedLanguage, code);
-
-            return (
-                '<div class="post-body--code">' +
-                    '<span class="post-body--code__language">' +
-                        HighlightedLanguages[usedLanguage] +
-                    '</span>' +
-                    '<pre>' +
-                        '<code class="hljs">' +
-                            parsed.value +
-                        '</code>' +
-                    '</pre>' +
-                '</div>'
-            );
-        } else if (usedLanguage === 'tex' || usedLanguage === 'latex') {
+        if (usedLanguage === 'tex' || usedLanguage === 'latex') {
             try {
                 const html = katex.renderToString(code, {throwOnError: false, displayMode: true});
 
@@ -144,13 +76,12 @@ class MattermostMarkdownRenderer extends marked.Renderer {
             }
         }
 
-        return (
-            '<pre>' +
-                '<code class="hljs">' +
-                    (escaped ? code : TextFormatting.sanitizeHtml(code)) + '\n' +
-                '</code>' +
-            '</pre>'
-        );
+        // treat html as xml to prevent injection attacks
+        if (usedLanguage === 'html') {
+            usedLanguage = 'xml';
+        }
+
+        return syntaxHightlighting.formatCode(usedLanguage, code);
     }
 
     codespan(text) {
diff --git a/webapp/utils/syntax_hightlighting.jsx b/webapp/utils/syntax_hightlighting.jsx
new file mode 100644
index 0000000000..981ce6b359
--- /dev/null
+++ b/webapp/utils/syntax_hightlighting.jsx
@@ -0,0 +1,197 @@
+// Copyright (c) 2016 Mattermost, Inc. All Rights Reserved.
+// See License.txt for license information.
+
+import * as Utils from './utils.jsx';
+import * as TextFormatting from './text_formatting.jsx';
+import Constants from './constants.jsx';
+
+import hlJS from 'highlight.js/lib/highlight.js';
+
+import hljsActionscript from 'highlight.js/lib/languages/actionscript.js';
+import hljsApplescript from 'highlight.js/lib/languages/applescript.js';
+import hljsBash from 'highlight.js/lib/languages/bash.js';
+import hljsClojure from 'highlight.js/lib/languages/clojure.js';
+import hljsCoffeescript from 'highlight.js/lib/languages/coffeescript.js';
+import hljsCpp from 'highlight.js/lib/languages/cpp.js';
+import hljsCs from 'highlight.js/lib/languages/cs.js';
+import hljsCss from 'highlight.js/lib/languages/css.js';
+import hljsD from 'highlight.js/lib/languages/d.js';
+import hljsDart from 'highlight.js/lib/languages/dart.js';
+import hljsDelphi from 'highlight.js/lib/languages/delphi.js';
+import hljsDiff from 'highlight.js/lib/languages/diff.js';
+import hljsDjango from 'highlight.js/lib/languages/django.js';
+import hljsDockerfile from 'highlight.js/lib/languages/dockerfile.js';
+import hljsErlang from 'highlight.js/lib/languages/erlang.js';
+import hljsFortran from 'highlight.js/lib/languages/fortran.js';
+import hljsFsharp from 'highlight.js/lib/languages/fsharp.js';
+import hljsGcode from 'highlight.js/lib/languages/gcode.js';
+import hljsGo from 'highlight.js/lib/languages/go.js';
+import hljsGroovy from 'highlight.js/lib/languages/groovy.js';
+import hljsHandlebars from 'highlight.js/lib/languages/handlebars.js';
+import hljsHaskell from 'highlight.js/lib/languages/haskell.js';
+import hljsHaxe from 'highlight.js/lib/languages/haxe.js';
+import hljsJava from 'highlight.js/lib/languages/java.js';
+import hljsJavascript from 'highlight.js/lib/languages/javascript.js';
+import hljsJson from 'highlight.js/lib/languages/json.js';
+import hljsJulia from 'highlight.js/lib/languages/julia.js';
+import hljsKotlin from 'highlight.js/lib/languages/kotlin.js';
+import hljsLess from 'highlight.js/lib/languages/less.js';
+import hljsLisp from 'highlight.js/lib/languages/lisp.js';
+import hljsLua from 'highlight.js/lib/languages/lua.js';
+import hljsMakefile from 'highlight.js/lib/languages/makefile.js';
+import hljsMarkdown from 'highlight.js/lib/languages/markdown.js';
+import hljsMatlab from 'highlight.js/lib/languages/matlab.js';
+import hljsObjectivec from 'highlight.js/lib/languages/objectivec.js';
+import hljsOcaml from 'highlight.js/lib/languages/ocaml.js';
+import hljsPerl from 'highlight.js/lib/languages/perl.js';
+import hljsPhp from 'highlight.js/lib/languages/php.js';
+import hljsPowershell from 'highlight.js/lib/languages/powershell.js';
+import hljsPuppet from 'highlight.js/lib/languages/puppet.js';
+import hljsPython from 'highlight.js/lib/languages/python.js';
+import hljsR from 'highlight.js/lib/languages/r.js';
+import hljsRuby from 'highlight.js/lib/languages/ruby.js';
+import hljsRust from 'highlight.js/lib/languages/rust.js';
+import hljsScala from 'highlight.js/lib/languages/scala.js';
+import hljsScheme from 'highlight.js/lib/languages/scheme.js';
+import hljsScss from 'highlight.js/lib/languages/scss.js';
+import hljsSmalltalk from 'highlight.js/lib/languages/smalltalk.js';
+import hljsSql from 'highlight.js/lib/languages/sql.js';
+import hljsSwift from 'highlight.js/lib/languages/swift.js';
+import hljsTex from 'highlight.js/lib/languages/tex.js';
+import hljsVbnet from 'highlight.js/lib/languages/vbnet.js';
+import hljsVbscript from 'highlight.js/lib/languages/vbscript.js';
+import hljsVerilog from 'highlight.js/lib/languages/verilog.js';
+import hljsXml from 'highlight.js/lib/languages/xml.js';
+import hljsYaml from 'highlight.js/lib/languages/yaml.js';
+
+hlJS.registerLanguage('actionscript', hljsActionscript);
+hlJS.registerLanguage('applescript', hljsApplescript);
+hlJS.registerLanguage('bash', hljsBash);
+hlJS.registerLanguage('clojure', hljsClojure);
+hlJS.registerLanguage('coffeescript', hljsCoffeescript);
+hlJS.registerLanguage('cpp', hljsCpp);
+hlJS.registerLanguage('cs', hljsCs);
+hlJS.registerLanguage('css', hljsCss);
+hlJS.registerLanguage('d', hljsD);
+hlJS.registerLanguage('dart', hljsDart);
+hlJS.registerLanguage('delphi', hljsDelphi);
+hlJS.registerLanguage('diff', hljsDiff);
+hlJS.registerLanguage('django', hljsDjango);
+hlJS.registerLanguage('dockerfile', hljsDockerfile);
+hlJS.registerLanguage('erlang', hljsErlang);
+hlJS.registerLanguage('fortran', hljsFortran);
+hlJS.registerLanguage('fsharp', hljsFsharp);
+hlJS.registerLanguage('gcode', hljsGcode);
+hlJS.registerLanguage('go', hljsGo);
+hlJS.registerLanguage('groovy', hljsGroovy);
+hlJS.registerLanguage('handlebars', hljsHandlebars);
+hlJS.registerLanguage('haskell', hljsHaskell);
+hlJS.registerLanguage('haxe', hljsHaxe);
+hlJS.registerLanguage('java', hljsJava);
+hlJS.registerLanguage('javascript', hljsJavascript);
+hlJS.registerLanguage('json', hljsJson);
+hlJS.registerLanguage('julia', hljsJulia);
+hlJS.registerLanguage('kotlin', hljsKotlin);
+hlJS.registerLanguage('less', hljsLess);
+hlJS.registerLanguage('lisp', hljsLisp);
+hlJS.registerLanguage('lua', hljsLua);
+hlJS.registerLanguage('makefile', hljsMakefile);
+hlJS.registerLanguage('markdown', hljsMarkdown);
+hlJS.registerLanguage('matlab', hljsMatlab);
+hlJS.registerLanguage('objectivec', hljsObjectivec);
+hlJS.registerLanguage('ocaml', hljsOcaml);
+hlJS.registerLanguage('perl', hljsPerl);
+hlJS.registerLanguage('php', hljsPhp);
+hlJS.registerLanguage('powershell', hljsPowershell);
+hlJS.registerLanguage('puppet', hljsPuppet);
+hlJS.registerLanguage('python', hljsPython);
+hlJS.registerLanguage('r', hljsR);
+hlJS.registerLanguage('ruby', hljsRuby);
+hlJS.registerLanguage('rust', hljsRust);
+hlJS.registerLanguage('scala', hljsScala);
+hlJS.registerLanguage('scheme', hljsScheme);
+hlJS.registerLanguage('scss', hljsScss);
+hlJS.registerLanguage('smalltalk', hljsSmalltalk);
+hlJS.registerLanguage('sql', hljsSql);
+hlJS.registerLanguage('swift', hljsSwift);
+hlJS.registerLanguage('tex', hljsTex);
+hlJS.registerLanguage('vbnet', hljsVbnet);
+hlJS.registerLanguage('vbscript', hljsVbscript);
+hlJS.registerLanguage('verilog', hljsVerilog);
+hlJS.registerLanguage('xml', hljsXml);
+hlJS.registerLanguage('yaml', hljsYaml);
+
+const HighlightedLanguages = Constants.HighlightedLanguages;
+
+export function formatCode(lang, data, filename) {
+    var language = lang || '';
+    var parsed;
+    var header = '';
+
+    language = language.toLowerCase();
+
+    if (HighlightedLanguages[language]) {
+        var name = HighlightedLanguages[language].name;
+
+        if (filename) {
+            const fname = decodeURIComponent(Utils.getFileName(filename));
+            name = fname + ' - ' + name;
+        }
+
+        header = '<span class="post-body--code__language">' + name + '</span>';
+
+        try {
+            parsed = hlJS.highlight(language, data).value;
+        } catch (e) {
+            parsed = TextFormatting.sanitizeHtml(data);
+        }
+    } else {
+        parsed = TextFormatting.sanitizeHtml(data);
+    }
+
+    const lines = data.match(/\r\n|\r|\n|$/g).length;
+    var strlines = '';
+    for (var i = 1; i <= lines; i++) {
+        if (strlines) {
+            strlines += '\n' + i;
+        } else {
+            strlines += i;
+        }
+    }
+
+    return (
+        '<div class="post-body--code">' +
+            header +
+            '<pre>' +
+                '<code class="hljs">' +
+                    '<table>' +
+                        '<tbody>' +
+                            '<tr>' +
+                                '<td class="post-body--code__lineno">' + strlines + '</td>' +
+                                '<td>' +
+                                    parsed +
+                                '</td>' +
+                            '</tr>' +
+                        '</tbody>' +
+                    '</table>' +
+                '</code>' +
+            '</pre>' +
+        '</div>'
+    );
+}
+
+export function getLang(filename) {
+    const fileInfo = Utils.splitFileLocation(filename);
+    var ext = fileInfo.ext;
+    if (!ext) {
+        return null;
+    }
+
+    ext = ext.toLowerCase();
+    for (var key in HighlightedLanguages) {
+        if (HighlightedLanguages[key].extensions.find((x) => x === ext)) {
+            return key;
+        }
+    }
+    return null;
+}
diff --git a/webapp/utils/utils.jsx b/webapp/utils/utils.jsx
index fbed9a0820..12a7ff50e9 100644
--- a/webapp/utils/utils.jsx
+++ b/webapp/utils/utils.jsx
@@ -680,7 +680,7 @@ export function applyTheme(theme) {
     }
 
     if (theme.centerChannelBg) {
-        changeCss('.app__content, .markdown__table, .markdown__table tbody tr, .suggestion-list__content, .modal .modal-content', 'background:' + theme.centerChannelBg, 1);
+        changeCss('.app__content, .markdown__table, .markdown__table tbody tr, .suggestion-list__content, .modal .modal-content, .modal .modal-back', 'background:' + theme.centerChannelBg, 1);
         changeCss('#post-list .post-list-holder-by-time', 'background:' + theme.centerChannelBg, 1);
         changeCss('#post-create', 'background:' + theme.centerChannelBg, 1);
         changeCss('.date-separator .separator__text, .new-separator .separator__text', 'background:' + theme.centerChannelBg, 1);