diff --git a/media/css/seahub.css b/media/css/seahub.css
index 83548fedf6..506569f054 100644
--- a/media/css/seahub.css
+++ b/media/css/seahub.css
@@ -3659,6 +3659,11 @@ img.thumbnail {
 .web-setting-input .input {
     margin:0;
 }
+.web-setting-input .textarea {
+    box-sizing:content-box;
+    height:95px;
+    margin:0;
+}
 .web-setting-ops {
     width:100px;
     vertical-align:top;
diff --git a/seahub/settings.py b/seahub/settings.py
index f108fb3d50..d55ad60d54 100644
--- a/seahub/settings.py
+++ b/seahub/settings.py
@@ -326,10 +326,7 @@ FILE_ENCODING_LIST = ['auto', 'utf-8', 'gbk', 'ISO-8859-1', 'ISO-8859-5']
 FILE_ENCODING_TRY_LIST = ['utf-8', 'gbk']
 HIGHLIGHT_KEYWORD = False # If True, highlight the keywords in the file when the visit is via clicking a link in 'search result' page.
 # extensions of previewed files
-TEXT_PREVIEW_EXT = """ac, am, bat, c, cc, cmake, cpp, cs, css, diff, el, h, html,
-htm, java, js, json, less, make, org, php, pl, properties, py, rb,
-scala, script, sh, sql, txt, text, tex, vi, vim, xhtml, xml, log, csv,
-groovy, rst, patch, go"""
+TEXT_PREVIEW_EXT = """ac, am, bat, c, cc, cmake, cpp, cs, css, diff, el, h, html, htm, java, js, json, less, make, org, php, pl, properties, py, rb, scala, script, sh, sql, txt, text, tex, vi, vim, xhtml, xml, log, csv, groovy, rst, patch, go"""
 
 # Common settings(file extension, storage) for avatar and group avatar.
 AVATAR_FILE_STORAGE = '' # Replace with 'seahub.base.database_storage.DatabaseStorage' if save avatar files to database
diff --git a/seahub/templates/snippets/web_settings_form.html b/seahub/templates/snippets/web_settings_form.html
index 22dda8d6c5..d3f031abcd 100644
--- a/seahub/templates/snippets/web_settings_form.html
+++ b/seahub/templates/snippets/web_settings_form.html
@@ -15,6 +15,21 @@
 </form>
 {% endif %}
 
+{% if type == 'textarea' %}
+<form class="web-setting-form web-textarea-setting-form" action="">
+    <h5 class="web-setting-name">{{ setting_display_name }}</h5>
+    <div class="web-setting-input">
+        <textarea class="textarea" name="{{ setting_name }}" data-cur="{{ setting_val }}">{{ setting_val }}</textarea>
+        <p class="error hide"></p>
+        <p class="tip">{{ help_tip }}</p>
+    </div>
+    <div class="web-setting-ops">
+        <button type="submit" class="submit sf2-icon-tick tick-green vam hide" title="{% trans "Submit" %}"></button>
+        <button type="button" class="cancel sf2-icon-x2 vam hide" title="{% trans "Cancel" %}"></button>
+    </div>
+</form>
+{% endif %}
+
 {% if type == 'checkbox' %}
 <form class="web-setting-form web-checkbox-setting-form" action="">{% csrf_token %}
     <h5 class="web-setting-name">{{ setting_display_name }}</h5>
diff --git a/seahub/templates/sysadmin/settings.html b/seahub/templates/sysadmin/settings.html
index d3a6d88097..cd24eeb529 100644
--- a/seahub/templates/sysadmin/settings.html
+++ b/seahub/templates/sysadmin/settings.html
@@ -43,7 +43,7 @@
 
     {% with type="checkbox" setting_name="ACTIVATE_AFTER_REGISTRATION" setting_val=config_dict.ACTIVATE_AFTER_REGISTRATION %}
         {% trans "activate after registration" as setting_display_name %}
-        {% trans "Activate user immediately after registration. If unchecked, an user need to be activated by administrator or via activation email" as help_tip %}
+        {% trans "Activate user immediately after registration. If unchecked, a user need to be activated by administrator or via activation email" as help_tip %}
         {% include "snippets/web_settings_form.html" %}
     {% endwith %}
 
@@ -116,13 +116,13 @@
 
     {% with type="checkbox" setting_name="ENABLE_REPO_HISTORY_SETTING" setting_val=config_dict.ENABLE_REPO_HISTORY_SETTING %}
         {% trans "library history" as setting_display_name %}
-        {% trans "Allow user to keep library history" as help_tip %}
+        {% trans "Allow user to change library history settings" as help_tip %}
         {% include "snippets/web_settings_form.html" %}
     {% endwith %}
 
     {% with type="checkbox" setting_name="ENABLE_ENCRYPTED_LIBRARY" setting_val=config_dict.ENABLE_ENCRYPTED_LIBRARY %}
         {% trans "encrypted library" as setting_display_name %}
-        {% trans "Allow user to create encrypted library" as help_tip %}
+        {% trans "Allow user to create encrypted libraries" as help_tip %}
         {% include "snippets/web_settings_form.html" %}
     {% endwith %}
 
@@ -132,18 +132,22 @@
         {% include "snippets/web_settings_form.html" %}
     {% endwith %}
 
-    {% with type="input" setting_name="SHARE_LINK_PASSWORD_MIN_LENGTH" setting_val=config_dict.SHARE_LINK_PASSWORD_MIN_LENGTH %} {% include "snippets/web_settings_form.html" %}
+    {% with type="input" setting_name="SHARE_LINK_PASSWORD_MIN_LENGTH" setting_val=config_dict.SHARE_LINK_PASSWORD_MIN_LENGTH %}
         {% trans "download/upload link password minimum length" as setting_display_name %}
         {% trans "The least number of characters a download/upload link password should include." as help_tip %}
-    {% endwith %}
-
-    {% with type="checkbox" setting_display_name="ENABLE_USER_CREATE_ORG_REPO" setting_name="ENABLE_USER_CREATE_ORG_REPO" setting_val=config_dict.ENABLE_USER_CREATE_ORG_REPO %}
-        {% trans "Allow user to add organization library. If unchecked, only system admin can add library." as help_tip %}
         {% include "snippets/web_settings_form.html" %}
     {% endwith %}
 
-    {% with type="input" setting_display_name="Preview File Extensions" setting_name="TEXT_PREVIEW_EXT" setting_val=config_dict.TEXT_PREVIEW_EXT %}
-        {% trans "Extensions of online previewed files, each suffix is separated by a comma." as help_tip %}
+    {% with type="checkbox" setting_display_name="ENABLE_USER_CREATE_ORG_REPO" setting_name="ENABLE_USER_CREATE_ORG_REPO" setting_val=config_dict.ENABLE_USER_CREATE_ORG_REPO %}
+        {% trans "Allow user to add organization libraries. Otherwise, only system admin can add organization libraries." as help_tip %}
+        {% include "snippets/web_settings_form.html" %}
+    {% endwith %}
+
+    <h4>{% trans "Online Preview" %}</h4>
+
+    {% with type="textarea" setting_name="TEXT_PREVIEW_EXT" setting_val=config_dict.TEXT_PREVIEW_EXT %}
+        {% trans "text file extensions" as setting_display_name %}
+        {% trans "Extensions of text files that can be online previewed, each suffix is separated by a comma." as help_tip %}
         {% include "snippets/web_settings_form.html" %}
     {% endwith %}
     
@@ -158,12 +162,11 @@
 
 {% block extra_script %}
 <script type="text/javascript">
-$('.web-setting-form .input').focus(function() {
+$('.input, .textarea', $('.web-setting-form')).focus(function() {
     var $otherFormSubmit = $('.web-setting-form .submit:visible');
     if ($otherFormSubmit.length > 0) {
         $otherFormSubmit.siblings('.cancel').click();
     }
-
     var $form = $(this).closest('form');
     $('.submit, .cancel', $form).show();
 });
@@ -178,7 +181,7 @@ $('.web-setting-form .cancel').click(function() {
 $(document).click(function(e) {
     var target =  e.target || event.srcElement;
     var $op = $('.web-setting-form .submit:visible');
-    if ($op.length && !$('.input, .submit, .cancel', $op.closest('form')).is(target)) {
+    if ($op.length && !$('.input, .textarea, .submit, .cancel', $op.closest('form')).is(target)) {
         $('.cancel', $op.closest('form')).click();
     }
 });
@@ -208,10 +211,10 @@ $('.web-setting-checkbox').change(function() {
     });
 });
 
-$('.web-input-setting-form').submit(function() {
+$('.web-input-setting-form, .web-textarea-setting-form').submit(function() {
     var $form = $(this),
         $error = $form.find('.error'),
-        $input = $form.find('.input'),
+        $input = $form.hasClass('web-input-setting-form') ? $('.input', $form) : $('.textarea', $form),
         $sb_btn = $('.submit', $form),
         $cancel_btn = $('.cancel', $form),
         key = $input.attr('name'),