Is there some way to make the box wider?
I wasn't even going to read this thread as it was marked Resolved. Yes you can make it as wide/narrow as you want with a couple of simple mods.
First, add a class attribute to the above code. Something like class="dropdown" so that code should now look like...
<select name="archive-menu" class="dropdown" onChange="document.location.href=this.options[this.selectedIndex].value;">
<option value="">Select month</option>
<?php query_posts('format=option');?>
</select>
Next add the styling info for that class to your style sheet. Something like...
.dropdown {
font-family: arial;
font-size: 9px;
color: #000000;
width:150px;
background-color: #FFFFFF;
}
Adjust the values the way you like.