А так?
[CODE]
<?require($_SERVER["DOCUMENT_ROOT"]."/bitrix/header.php");?>
<?CUtil::InitJSCore(array('window'));?>
<script>
BX.ready(function(){
var Dialog = new BX.CDialog({
title: "Заголовок окна",
head: 'Текст до формы',
content: '<form method="POST" style="overflow:hidden;" action="/search/" id="searchform">\
<textarea name="search" style="height: 78px; width: 374px;">Ищем много текста</textarea>\
</form>',
icon: 'head-block',
resizable: true,
draggable: true,
height: '168',
width: '400',
buttons: ['<input type="submit" value="test" />', BX.CDialog.btnSave, BX.CDialog.btnCancel, BX.CDialog.btnClose]
});Dialog.Show();
});
</script>
<?require($_SERVER["DOCUMENT_ROOT"]."/bitrix/footer.php");?>
[/CODE]