[silver18]

Here's how I solved the problem...Not elegant at all, but it works..
(actually a part of my ImageGallery WAF)

<form>
<select id="jumpToBook" name="selectedBookmark" onchange="jumpToBookmark(this.form.selectedBookmark);" style="position: fixed; left:20px; top:113px; z-index: 2;">
<option style="display:none;" value="" disabled="disabled">No bookmarks available!</option>
</select>
</form>

and here's the relevant part of the jumpToBookmark function:

var selpage;
var wheretobook;

function jumpToBookmark (wheretobook) {
selpage = wheretobook.options[wheretobook.selectedIndex].value;
}

I found that 5.1.0 firmware has lots of problems with select menus' style: so avoid fixed width and be careful with z-index (selects like to stay on top!).