diff --git a/koha-tmpl/intranet-tmpl/prog/en/modules/tools/viewlog.tt b/koha-tmpl/intranet-tmpl/prog/en/modules/tools/viewlog.tt
index 85090b3ccb..525a590755 100644
--- a/koha-tmpl/intranet-tmpl/prog/en/modules/tools/viewlog.tt
+++ b/koha-tmpl/intranet-tmpl/prog/en/modules/tools/viewlog.tt
@@ -16,22 +16,49 @@
 	[% END %]
 </title>
 [% INCLUDE 'doc-head-close.inc' %]
-<style>
-fieldset.rows label.viewlog {
-    float: none;
-    font-weight: normal;
-    margin: 0;
-    min-width: 9em;
-    padding: .5em;
-    text-align: left;
-    white-space: nowrap;
-    width: auto;
-}
-.log_modules {
-    display: flex;
-    flex-wrap: wrap;
-}
-</style>
+[% Asset.css("css/humanmsg.css") | $raw %]
+[% FILTER collapse %]
+    <style>
+        fieldset.rows label.viewlog {
+            float: none;
+            font-weight: normal;
+            margin: 0;
+            min-width: 9em;
+            padding: .5em;
+            text-align: left;
+            white-space: nowrap;
+            width: auto;
+        }
+        .log_modules {
+            display: flex;
+            flex-wrap: wrap;
+        }
+        .compare_info {
+            background-color: #E6F0F2;
+            margin: .5em -.5em -.5em -.5em;
+            padding: .5em;
+            text-align: right;
+        }
+        .modal-dialog {
+            width : 90%;
+        }
+        /* jsdiff styles */
+        ins {
+            background-color: #e6ffe6;
+        }
+        del {
+            background-color: #ffe6e6;
+        }
+        #col1 ins,
+        #col2 del {
+            display: none;
+        }
+        pre {
+            overflow: scroll;
+            padding: 10px;
+        }
+    </style>
+[% END %]
 </head>
 
 <body id="tools_viewlog" class="tools">
@@ -225,6 +252,10 @@ fieldset.rows label.viewlog {
                 [% IF ( do_it ) %]
                     [% IF ( total ) %]
                         <h3>Log entries</h3>
+                        <div id="toolbar" class="btn-toolbar">
+                            <a href="#" id="select_none" class="btn btn-link disabled"><i class="fa fa-remove"></i> Check none</a>
+                            <button class="btn btn-link disabled compare_link"><i class="fa fa-columns"></i> Compare selected</button>
+                        </div>
                         <table id="logst">
                             <thead>
                                 <tr>
@@ -284,7 +315,18 @@ fieldset.rows label.viewlog {
                                         [% IF ( loopro.module == 'CIRCULATION' ) %]
                                             <a href="/cgi-bin/koha/catalogue/moredetail.pl?itemnumber=[% loopro.info | uri %]&amp;biblionumber=[% loopro.biblionumber | uri %]&amp;bi=[% loopro.biblioitemnumber | uri %]#item[% loopro.info | uri %]" title="Display detail for this item">Item [% loopro.barcode | html %]</a>
                                         [% ELSE %]
-                                            [% loopro.info | html %]
+                                            [% IF loopro.module == "SYSTEMPREFERENCE" %]
+                                                <div class="loginfo" id="loginfo[% loopro.action_id | html %]">
+                                                    [% loopro.info | html %]
+                                                </div>
+                                                <div class="compare_info" id="compare_info[% loopro.action_id | html %]">
+                                                    <label><input type="checkbox" name="diff" id="action_id[% loopro.action_id | html %]" data-actionid="[% loopro.action_id | html %]" data-filter="[% FOREACH info IN loopro.info.split(' \| ') %][% IF loop.first %][% info | html %][% END %][% END %]" class="compare" /> Compare</label>
+                                                </div>
+                                            [% ELSE %]
+                                                <div class="loginfo" id="loginfo[% loopro.action_id | html %]">
+                                                    [% loopro.info | html %]
+                                                </div>
+                                            [% END %]
                                         [% END %]
                                     </td>
                                     <td>[% PROCESS translate_log_interface log_interface=loopro.interface %]</td>
@@ -325,15 +367,44 @@ fieldset.rows label.viewlog {
         </div> <!-- /.col-sm-2.col-sm-pull-10 -->
      </div> <!-- /.row -->
 
+<div class="modal" id="compareInfo" tabindex="-1" role="dialog" aria-labelledby="compareInfoLabel">
+    <div class="modal-dialog modal-lg" role="document">
+        <div class="modal-content">
+            <div class="modal-header">
+                <button type="button" class="closebtn" data-dismiss="modal" aria-label="Close"><span aria-hidden="true">&times;</span></button>
+                <h4 class="modal-title" id="compareInfoLabel">Compare preference values</h4>
+            </div>
+            <div class="modal-body">
+                <div class="row">
+                    <div class="compare_pane col-sm-6" id="col1">
+                        <h5>Older version</h5>
+                        <pre></pre>
+                    </div>
+                    <div class="compare_pane col-sm-6" id="col2">
+                        <h5>Newer version</h5>
+                        <pre></pre>
+                    </div>
+                </div>
+            </div> <!-- /.modal-body -->
+            <div class="modal-footer">
+                <button type="button" class="btn btn-default deny" data-dismiss="modal">Close</button>
+            </div>
+        </div> <!-- /.modal-content -->
+    </div> <!-- /.modal-dialog -->
+</div> <!-- /#compareInfo -->
+
 [% MACRO jsinclude BLOCK %]
     [% INCLUDE 'calendar.inc' %]
     [% INCLUDE 'datatables.inc' %]
     [% INCLUDE 'columns_settings.inc' %]
+    [% Asset.js("lib/jquery/plugins/humanmsg.js") | $raw %]
     [% Asset.js("js/tools-menu.js") | $raw %]
+    [% Asset.js("lib/hc-sticky.js") | $raw %]
     [% IF ( circulation ) %]
         [% INCLUDE 'str/members-menu.inc' %]
         [% Asset.js("js/members-menu.js") | $raw %]
     [% END %]
+    [% Asset.js("lib/jsdiff/jsdiff.min.js") | $raw %]
     <script>
         var columns_settings = [% TablesSettings.GetColumns('tools', 'logviewer', 'logst', 'json') | $raw %];
     </script>
diff --git a/koha-tmpl/intranet-tmpl/prog/js/viewlog.js b/koha-tmpl/intranet-tmpl/prog/js/viewlog.js
index 1354c95e0a..04eb6c7b2f 100644
--- a/koha-tmpl/intranet-tmpl/prog/js/viewlog.js
+++ b/koha-tmpl/intranet-tmpl/prog/js/viewlog.js
@@ -1,3 +1,5 @@
+var Sticky;
+
 function tickAll(section){
     $("input[type='checkbox'][name='" + section + "']").prop("checked", true);
     $("#" + section.slice(0,-1) + "ALL").prop("checked", true);
@@ -10,7 +12,52 @@ function untickAll(section){
     $("input[type='checkbox'][name='" + section + "']").prop("disabled", false);
 }
 
+function limitCheckboxes() {
+    var checkboxes = $(".compare");
+    var limit = 2;
+    var compare_link = '<a href="#" class="btn btn-link compare_link"><i class="fa fa-columns"></i> ' + __("View comparison") + '</a>';
+    checkboxes.each(function(){
+        $(this).on("change", function(){
+            var checked = [];
+            checkboxes.each(function () {
+                if( $(this).prop("checked") ){
+                    checked.push( $(this).data("actionid") );
+                }
+            });
+            if (checked.length > 0) {
+                $("#select_none").removeClass("disabled");
+            } else {
+                $("#select_none").addClass("disabled");
+                $("#logst").DataTable().search("").draw();
+            }
+            if( checked.length == 1 ){
+                $("#logst").DataTable().search($(this).data("filter")).draw();
+                humanMsg.displayAlert( __("Showing results for %s").format( $(this).data("filter") ) );
+            }
+            if( checked.length == 2 ){
+                $("#compare_info" + checked[0]).prepend( compare_link );
+                $("#compare_info" + checked[1]).prepend( compare_link );
+                $("button.compare_link").removeClass("disabled");
+            } else if (checked.length > limit) {
+                humanMsg.displayAlert( __("You can select maximum of two checkboxes") );
+                $(this).prop("checked", false );
+            } else if (checked.length < limit) {
+                $("a.compare_link").remove();
+                $("button.compare_link").addClass("disabled");
+            }
+        });
+    });
+}
+
 $(document).ready(function(){
+    limitCheckboxes();
+    if ($('#toolbar').length) {
+        Sticky = $("#toolbar");
+        Sticky.hcSticky({
+            stickTo: "main",
+            stickyClass: "floating"
+        });
+    }
 
     if ( $('input[type="checkbox"][name="modules"]:checked').length == 0 ) {
         tickAll('modules');
@@ -67,4 +114,27 @@ $(document).ready(function(){
         "order": [[0, "desc"]],
         "pagingType" : "full"
     }, columns_settings);
+
+    $("body").on("click", ".compare_link", function(e){
+        e.preventDefault();
+        if( $(this).hasClass('disabled') ){
+            humanMsg.displayAlert( __("You must select two entries to compare") );
+        } else {
+            var firstid = $(".compare:checked").eq(0).data("actionid");
+            var secondid = $(".compare:checked").eq(1).data("actionid");
+            var firstvalue = $("#loginfo" + firstid).text();
+            var secondvalue = $("#loginfo" + secondid).text();
+            var diffs = diffString(secondvalue, firstvalue);
+            $("#col1 pre,#col2 pre").html(diffs);
+            $("#compareInfo").modal("show");
+        }
+    });
+    $("#compareInfo").on("hidden.bs.modal", function(){
+        $("#col1 pre,#col2 pre").html("");
+    });
+
+    $("#select_none").on("click", function(e){
+        e.preventDefault();
+        $(".compare:checked").prop("checked", false).change();
+    });
 });