<listbox id="file_attach_list" multiple="true" checkbox="true" sizedByContent="true">
    <listhead>
        <listheader label="File Name"/>
        <listheader label="Size (bytes)"/>
    </listhead>
    <template name="model">
        <listitem>
            <listcell label="${each.filename}"/>
            <listcell label="${each.filesize}"/>
        </listitem>
    </template>
</listbox>

@Wire("#file_attach_list")
private Listbox fileAttachList;

private ListModelList<FileAttachModel> attachList = new ListModelList<FileAttachModel>();

@Override
public void doAfterCompose(Window win) throws Exception {
    super.doAfterCompose(win);

    attachList.setMultiple(true);
    fileAttachList.setModel(attachList);

    populateList();

    disableControls();
}

/* ... other methods, including one that populates the list */

private void disableControls() {
    fileAttachList.setDisabled(true);
}