MainWindow.ui (Código)

<?xml version="1.0" encoding="UTF-8"?>
<!-- Generated with glade 3.38.2 -->
<interface>
    <requires lib="gtk+" version="3.24"/>
    <object class="GtkImage" id="image1">
        <property name="visible">True</property>
        <property name="can-focus">False</property>
        <property name="icon-name">system-search-symbolic</property>
    </object>
    <template class="MainWindow" parent="GtkApplicationWindow">
        <property name="can-focus">False</property>
        <property name="default-width">683</property>
        <property name="default-height">384</property>
        <property name="icon">../../../assets/icons/icon.png</property>
        <signal name="key-press-event" handler="key_press_event" swapped="no"/>
        <child>
            <object class="GtkBox">
                <property name="visible">True</property>
                <property name="can-focus">False</property>
                <property name="orientation">vertical</property>
                <child>
                    <object class="GtkSearchBar" id="search_bar">
                        <property name="visible">True</property>
                        <property name="can-focus">False</property>
                        <child>
                            <object class="GtkEntry">
                                <property name="visible">True</property>
                                <property name="can-focus">True</property>
                            </object>
                        </child>
                    </object>
                    <packing>
                        <property name="expand">False</property>
                        <property name="fill">True</property>
                        <property name="position">0</property>
                    </packing>
                </child>
                <child>
                    <object class="GtkLabel">
                        <property name="visible">True</property>
                        <property name="can-focus">False</property>
                        <property name="xpad">12</property>
                        <property name="label" translatable="yes">Pressione &lt;b&gt;&lt;tt&gt;Ctrl+f&lt;/tt&gt;&lt;/b&gt;
                            para abrir a pesquisa ou clique no ícone de pesquisa na barra de título.
                        </property>
                        <property name="use-markup">True</property>
                        <property name="wrap">True</property>
                    </object>
                    <packing>
                        <property name="expand">True</property>
                        <property name="fill">True</property>
                        <property name="position">1</property>
                    </packing>
                </child>
            </object>
        </child>
        <child type="titlebar">
            <object class="GtkHeaderBar">
                <property name="visible">True</property>
                <property name="can-focus">False</property>
                <property name="title" translatable="yes">Gtk.SearchBar</property>
                <property name="subtitle" translatable="yes">Gtk.SearchBar</property>
                <property name="show-close-button">True</property>
                <child>
                    <object class="GtkToggleButton" id="btn_search">
                        <property name="visible">True</property>
                        <property name="can-focus">True</property>
                        <property name="receives-default">True</property>
                        <property name="image">image1</property>
                        <signal name="clicked" handler="on_btn_search_clicled" swapped="no"/>
                    </object>
                </child>
            </object>
        </child>
    </template>
</interface>