Not working
if possible solve it

Thank you very much for your reply,But the code reported an error,odoo.addons.web.controllers.binary: Parsing asset bundle web.assets_web.min.js has failed: file '/web_search_panel_hide_show/static/src/xml/search_panel.xml' The template name is missing。

I checked the cause and found that the error was caused by the <odoo> tag you added, but I still didn't see the effect I needed after I repaired it

Hi,

You can use the following code for adding a new div in the search panel.

<?xml version="1.0" encoding="UTF-8"?>

<odoo>

<templates>

    <t t-name="SearchPanelContent" t-inherit="web.SearchPanelContent" t-inherit-mode="extension">

        <xpath expr="//div[hasclass('o_search_panel')]" position="inside">

            <div class="o_search_panel_control fa fa-long-arrow-left btn btn-icon" id='o_search_panel_control'

                 t-on-click="click_search_panel"/>

        </xpath>

    </t>

</templates>

</odoo>

Hope it helps,