diff --git a/web_dialog_size/__manifest__.py b/web_dialog_size/__manifest__.py
index a5be6d098..9e6bb8360 100644
--- a/web_dialog_size/__manifest__.py
+++ b/web_dialog_size/__manifest__.py
@@ -15,10 +15,21 @@
     "Odoo Community Association (OCA)",
     "website": "https://github.com/OCA/web",
     "category": "web",
-    "version": "14.0.1.0.0",
+    "version": "15.0.1.0.0",
     "license": "AGPL-3",
     "depends": ["web"],
-    "qweb": ["static/src/xml/web_dialog_size.xml"],
-    "data": ["templates/assets.xml"],
     "installable": True,
+    "assets": {
+        "web.assets_backend": [
+            "/web_dialog_size/static/src/js/web_dialog_size.js",
+            "/web_dialog_size/static/src/js/web_dialog_size.esm.js",
+            "/web_dialog_size/static/src/js/web_dialog_draggable.esm.js",
+            "/web_dialog_size/static/src/scss/web_dialog_size.scss",
+        ],
+        "web.assets_qweb": [
+            "/web_dialog_size/static/src/xml/web_dialog_size.xml",
+            "/web_dialog_size/static/src/xml/ExpandButton.xml",
+            "/web_dialog_size/static/src/xml/DialogDraggable.xml",
+        ],
+    },
 }
diff --git a/web_dialog_size/readme/CONTRIBUTORS.rst b/web_dialog_size/readme/CONTRIBUTORS.rst
index 9da11ab82..5f67550d1 100644
--- a/web_dialog_size/readme/CONTRIBUTORS.rst
+++ b/web_dialog_size/readme/CONTRIBUTORS.rst
@@ -13,3 +13,4 @@
 
 * Sudhir Arya <sudhir@erpharbor.com>
 * Pierre Pizzetta <pierre@devreaction.com>
+* Mantas Šniukas <mantas@vialaurea.lt>
diff --git a/web_dialog_size/static/src/js/web_dialog_draggable.esm.js b/web_dialog_size/static/src/js/web_dialog_draggable.esm.js
new file mode 100644
index 000000000..f47eae5fc
--- /dev/null
+++ b/web_dialog_size/static/src/js/web_dialog_draggable.esm.js
@@ -0,0 +1,52 @@
+/** @odoo-module **/
+
+import {patch} from "@web/core/utils/patch";
+import {Dialog} from "@web/core/dialog/dialog";
+const {useExternalListener} = owl.hooks;
+import {useListener} from "web.custom_hooks";
+const {Component} = owl;
+
+export class DialogDraggable extends Component {
+    setup() {
+        this.element_position = {x: 0, y: 0};
+        this.mouse_to_element_ratio = {x: 0, y: 0};
+        const bound_onDrag = this.onDrag.bind(this);
+        useListener("mousedown", "header.modal-header", (event) => {
+            const y = parseInt(this.el.offsetTop, 10);
+            const x = parseInt(this.el.offsetLeft, 10);
+            this.mouse_to_element_ratio = {x: event.x - x, y: event.y - y};
+            this.element_position = {
+                x: event.x - this.mouse_to_element_ratio.x - x,
+                y: event.y - this.mouse_to_element_ratio.y - y,
+            };
+            document.addEventListener("mousemove", bound_onDrag);
+        });
+        useExternalListener(document, "mouseup", () =>
+            document.removeEventListener("mousemove", bound_onDrag)
+        );
+    }
+    mounted() {
+        this.el.classList.add("position-absolute");
+        this.el.offsetParent.classList.add("position-relative");
+    }
+    getMovePosition({x, y}) {
+        return {
+            x: x - this.mouse_to_element_ratio.x - this.element_position.x,
+            y: y - this.mouse_to_element_ratio.y - this.element_position.y,
+        };
+    }
+    onDrag(event) {
+        const {x, y} = this.getMovePosition(event);
+        this.el.style.left = `${x}px`;
+        this.el.style.top = `${y}px`;
+    }
+}
+
+DialogDraggable.template = "DialogDraggable";
+
+patch(Dialog, "web_dialog_size.DialogDraggable", {
+    components: {
+        ...Dialog.components,
+        DialogDraggable,
+    },
+});
diff --git a/web_dialog_size/static/src/js/web_dialog_size.esm.js b/web_dialog_size/static/src/js/web_dialog_size.esm.js
new file mode 100644
index 000000000..c3f5a083e
--- /dev/null
+++ b/web_dialog_size/static/src/js/web_dialog_size.esm.js
@@ -0,0 +1,60 @@
+/** @odoo-module **/
+
+import {ActionDialog} from "@web/webclient/actions/action_dialog";
+import {patch} from "@web/core/utils/patch";
+import rpc from "web.rpc";
+const {Component} = owl;
+const {onMounted} = owl.hooks;
+
+export class ExpandButton extends Component {
+    setup() {
+        this.last_size = this.props.getsize();
+        this.config = rpc.query({
+            model: "ir.config_parameter",
+            method: "get_web_dialog_size_config",
+        });
+
+        onMounted(() => {
+            var self = this;
+            this.config.then(function (r) {
+                if (r.default_maximize && stop) {
+                    self.dialog_button_extend();
+                }
+            });
+        });
+    }
+
+    dialog_button_extend() {
+        this.props.setsize("dialog_full_screen");
+    }
+
+    dialog_button_restore() {
+        this.props.setsize(this.last_size);
+    }
+}
+
+ExpandButton.template = "web_dialog_size.ExpandButton";
+
+patch(ActionDialog.prototype, "web_dialog_size.ActionDialog", {
+    setup() {
+        this._super(...arguments);
+        this.setSize = this.setSize.bind(this);
+        this.getSize = this.getSize.bind(this);
+    },
+
+    setSize(size) {
+        this.size = size;
+        this.render();
+    },
+
+    getSize() {
+        return this.size;
+    },
+});
+
+patch(ActionDialog, "web_dialog_size.ActionDialog", {
+    components: {
+        ...ActionDialog.components,
+        ExpandButton,
+    },
+});
diff --git a/web_dialog_size/static/src/xml/DialogDraggable.xml b/web_dialog_size/static/src/xml/DialogDraggable.xml
new file mode 100644
index 000000000..6cafd8641
--- /dev/null
+++ b/web_dialog_size/static/src/xml/DialogDraggable.xml
@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="utf-8" ?>
+<templates>
+    <t t-name="DialogDraggable" owl="1">
+        <t t-slot="default" />
+    </t>
+</templates>
diff --git a/web_dialog_size/static/src/xml/ExpandButton.xml b/web_dialog_size/static/src/xml/ExpandButton.xml
new file mode 100644
index 000000000..22318ef73
--- /dev/null
+++ b/web_dialog_size/static/src/xml/ExpandButton.xml
@@ -0,0 +1,21 @@
+<?xml version="1.0" encoding="utf-8" ?>
+<templates>
+    <t t-name="web_dialog_size.ExpandButton" owl="1">
+        <button
+            t-if="props.getsize() == 'dialog_full_screen'"
+            type="button"
+            class="close dialog_button_extend"
+            t-on-click="dialog_button_restore"
+        >
+            <i class="fa fa-compress" />
+        </button>
+        <button
+            t-if="props.getsize() != 'dialog_full_screen'"
+            type="button"
+            class="close dialog_button_restore"
+            t-on-click="dialog_button_extend"
+        >
+            <i class="fa fa-expand" />
+        </button>
+    </t>
+</templates>
diff --git a/web_dialog_size/static/src/xml/web_dialog_size.xml b/web_dialog_size/static/src/xml/web_dialog_size.xml
index d43a79b73..e7cc3a7b6 100644
--- a/web_dialog_size/static/src/xml/web_dialog_size.xml
+++ b/web_dialog_size/static/src/xml/web_dialog_size.xml
@@ -1,5 +1,7 @@
 <?xml version="1.0" encoding="UTF-8" ?>
-<templates id="template" xml:space="preserve">
+<templates xml:space="preserve">
+    <!-- This is for old Dialog template.
+    Because Odoo haven't done every template to OWL. -->
     <t t-extend="Dialog">
         <t t-jquery="button.close" t-operation="inner">
             <i class="fa fa-close" />
@@ -13,4 +15,16 @@
             </button>
         </t>
     </t>
+
+    <t t-inherit="web.ActionDialog" t-inherit-mode="extension" owl="1">
+        <xpath expr="//div[hasclass('modal-content')]" position="before">
+            <DialogDraggable />
+        </xpath>
+        <DialogDraggable position="inside">
+            <xpath expr="//div[hasclass('modal-content')]" position="move" />
+        </DialogDraggable>
+        <xpath expr="//button[hasclass('close')]" position="before">
+            <ExpandButton getsize="getSize" setsize="setSize" />
+        </xpath>
+    </t>
 </templates>
diff --git a/web_dialog_size/templates/assets.xml b/web_dialog_size/templates/assets.xml
deleted file mode 100644
index cb68c4697..000000000
--- a/web_dialog_size/templates/assets.xml
+++ /dev/null
@@ -1,19 +0,0 @@
-<?xml version="1.0" encoding="UTF-8" ?>
-<odoo>
-    <template
-        id="assets_backend"
-        name="web_dialog_size assets"
-        inherit_id="web.assets_backend"
-    >
-        <xpath expr="." position="inside">
-            <link
-                rel="stylesheet"
-                href="/web_dialog_size/static/src/scss/web_dialog_size.scss"
-            />
-            <script
-                type="text/javascript"
-                src="/web_dialog_size/static/src/js/web_dialog_size.js"
-            />
-        </xpath>
-    </template>
-</odoo>