plugins/sys/templates/admin/admin_messages/popup_add.stpl
<div style="width:400px;">
<p> {t(Admin Message for user)}: <a href="{account_link}" target="_blank"><b>{user_name}</b></a></p>
<br />
<div class="editform">
<form action="{form_action}" method="post">
<p>
<label for="title"><small>{t(Title)}</small></label>
<input type="text" id="title" name="title" value="">
</p>
<p>
<label><small>{t(Text)}</small></label>
<textarea name="text" cols="50" rows="8" style="width:100%;height:80%;"></textarea>
</p>
<div class="button_div">
<input type="submit" name="go" value="{t(Send)}">
</div>
</form>
</div>
<div align="center"><a href="javascript:void(0)" onclick="self.window.close();">{t(Close Window)}</a></div>
</div>