diff --git a/runbot/static/src/js/fields/diff_display.js b/runbot/static/src/js/fields/diff_display.js
new file mode 100644
index 00000000..074364de
--- /dev/null
+++ b/runbot/static/src/js/fields/diff_display.js
@@ -0,0 +1,79 @@
+import { Component, onWillRender } from '@odoo/owl';
+
+import { diff_match_patch } from "@runbot/libs/diff_match_patch/diff_match_patch";
+
+
+export class DiffDisplay extends Component {
+    static template = 'runbot.DiffDisplay';
+    static props = {
+        fromValue: { type: String },
+        toValue: { type: String },
+        lineFilter: { type: Function },
+    }
+    static defaultProps = {
+        lineFilter: (line) => line.type !== 'kept',
+    }
+
+    setup() {
+        onWillRender(() => {
+            this.lines = this.makeLines(this.props.fromValue, this.props.toValue);
+        });
+    }
+
+    makeLines(oldValue, newValue) {
+        const diff = this.makeDiff(oldValue, newValue);
+        const lines = this.prepareForRendering(diff);
+        return lines;
+    }
+
+    makeDiff(text1, text2) {
+        const dmp = new diff_match_patch();
+        const a = dmp.diff_linesToChars_(text1, text2);
+        const lineText1 = a.chars1;
+        const lineText2 = a.chars2;
+        const lineArray = a.lineArray;
+        const diffs = dmp.diff_main(lineText1, lineText2, false);
+        dmp.diff_charsToLines_(diffs, lineArray);
+        dmp.diff_cleanupSemantic(diffs);
+        return diffs;
+    }
+
+    prepareForRendering(diffs) {
+        let preLineCounter = 0;
+        let postLineCounter = 0;
+        return diffs.reduce((lines, {0: diff_type, 1: data}) => {
+            data.split('\n').forEach(line => {
+                line = line
+                    .replace(/&/g, '&')
+                    .replace(/</g, '&lt;')
+                    .replace(/>/g, '&gt;');
+                let type, colOne, colTwo;
+                switch (diff_type) {
+                    case 0: //kept
+                        type = 'kept'
+                        colOne = ''
+                        colTwo = postLineCounter;
+                        preLineCounter++; postLineCounter++;
+                        break;
+                    case -1: //removed
+                        type = 'removed';
+                        colOne = preLineCounter;
+                        colTwo = '-';
+                        preLineCounter++;
+                        break;
+                    case 1: //added
+                        type = 'added';
+                        colOne = '+';
+                        colTwo = postLineCounter;
+                        postLineCounter++;
+                        break;
+                    default:
+                        console.warn('Unknown diff_type', diff_type)
+                        return;
+                }
+                lines.push({type, colOne, colTwo, line});
+            })
+            return lines
+        }, []);
+    }
+}
diff --git a/runbot/static/src/js/fields/diff_display.xml b/runbot/static/src/js/fields/diff_display.xml
new file mode 100644
index 00000000..3e3f46ba
--- /dev/null
+++ b/runbot/static/src/js/fields/diff_display.xml
@@ -0,0 +1,14 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<templates>
+    <t t-name="runbot.DiffDisplay">
+        <div class="code_diff">
+            <table>
+                <tr t-foreach="lines" t-as="line" t-key="line_index" t-if="props.lineFilter(line)">
+                    <td class="col_number" t-out="line.colOne"/>
+                    <td class="col_number" t-out="line.colTwo"/>
+                    <td class="code" t-att-class="line.type" t-out="line.line"/>
+                </tr>
+            </table>
+        </div>
+    </t>
+</templates>
diff --git a/runbot/static/src/js/fields/tracking_value.js b/runbot/static/src/js/fields/tracking_value.js
index b6403748..c5cae058 100644
--- a/runbot/static/src/js/fields/tracking_value.js
+++ b/runbot/static/src/js/fields/tracking_value.js
@@ -2,6 +2,11 @@
 import { patch } from "@web/core/utils/patch";
 import { Message } from "@mail/core/common/message";
 import { diff_match_patch } from "@runbot/libs/diff_match_patch/diff_match_patch";
+import { DiffDisplay } from './diff_display';
+
+patch(Message, {
+    components: {...Message.components, DiffDisplay},
+});
 
 patch(Message.prototype, {
     setup() {
@@ -13,9 +18,6 @@ patch(Message.prototype, {
         const newValue = trackingValue.newValue.value;
         return ((oldValue && typeof oldValue=== 'string' && oldValue.includes('\n')) && (newValue && typeof oldValue=== 'string' && newValue.includes('\n')))
     },
-    formatTracking(trackingType, trackingValue) {
-        return super.formatTracking(trackingType, trackingValue) 
-    },
     toggleKept() {
         this.kept = !this.kept;
     },
@@ -29,52 +31,4 @@ patch(Message.prototype, {
             navigator.clipboard.writeText(trackingValue.newValue.value);
         };
     },
-    lines(trackingValue) {
-        const oldValue = trackingValue.oldValue.value;
-        const newValue = trackingValue.newValue.value;
-        const diff = this.makeDiff(oldValue, newValue);
-        const lines = this.prepareForRendering(diff);
-        return lines;
-    },
-    makeDiff(text1, text2) {
-        var dmp = new diff_match_patch();
-        var a = dmp.diff_linesToChars_(text1, text2);
-        var lineText1 = a.chars1;
-        var lineText2 = a.chars2;
-        var lineArray = a.lineArray;
-        var diffs = dmp.diff_main(lineText1, lineText2, false);
-        dmp.diff_charsToLines_(diffs, lineArray);
-        dmp.diff_cleanupSemantic(diffs);
-        return diffs;
-    },
-    prepareForRendering(diffs) {
-        var lines = [];
-        var pre_line_counter = 0
-        var post_line_counter = 0
-        for (var x = 0; x < diffs.length; x++) {
-            var diff_type = diffs[x][0];
-            var data = diffs[x][1];
-            var data_lines = data.split('\n');
-            for (var line_index in data_lines) {
-                var line = data_lines[line_index];
-                line = line.replace(/&/g, '&amp;');
-                line = line.replace(/</g, '&lt;');
-                line = line.replace(/>/g, '&gt;');
-                //text = text.replace(/\n/g, '<br>');
-                //text = text.replace(/ /g, '&nbsp&nbsp');
-                if (diff_type == -1) {
-                    lines.push({type:'removed', pre_line_counter: pre_line_counter, post_line_counter: '-', line: line})
-                    pre_line_counter += 1
-                } else if (diff_type == 0) {
-                    lines.push({type:'kept', pre_line_counter: '', post_line_counter: post_line_counter, line: line})
-                    pre_line_counter += 1
-                    post_line_counter +=1
-                } else if (diff_type == 1) {
-                    lines.push({type:'added', pre_line_counter: '+', post_line_counter: post_line_counter, line: line})
-                    post_line_counter +=1
-                }
-            }
-        }
-        return lines;
-      },
 });
diff --git a/runbot/static/src/js/fields/tracking_value.xml b/runbot/static/src/js/fields/tracking_value.xml
index 9aaca233..16efe135 100644
--- a/runbot/static/src/js/fields/tracking_value.xml
+++ b/runbot/static/src/js/fields/tracking_value.xml
@@ -10,17 +10,10 @@
                         <button class="btn btn-sm btn-outline-primary" t-on-click="copyNewToClipboard(trackingValue)">Copy new value to clipboard</button>
                     </div>
                     <div class="o-mail-Message-trackingField ms-1 fst-italic text-muted">(<t t-out="trackingValue.changedField"/>)</div>
-                    <div class="code_diff">
-                        <table>
-                            <t t-foreach="lines(trackingValue)" t-as="line" t-key="line_index">
-                                <tr t-if="kept or line.type!=='kept'">
-                                    <td class="col_number" t-out="line.pre_line_counter"/>
-                                    <td class="col_number" t-out="line.post_line_counter"/>
-                                    <td class="code" t-att-class="line.type" t-out="line.line"/>
-                                </tr>
-                            </t>
-                        </table>
-                    </div>
+                    <DiffDisplay
+                        fromValue="trackingValue.oldValue.value" toValue="trackingValue.newValue.value"
+                        lineFilter="kept ? () => true : undefined"
+                    />
                 </t>
                 <t t-else="">
                     <span class="o-mail-Message-trackingOld me-1 px-1 text-muted fw-bold" t-out="formatTrackingOrNone(trackingValue.fieldType, trackingValue.oldValue)"/>