CSS side-by-side DIVs - Dynatree doesn't fill horizontally

Question

I have two side-by-side DIVs in a JSP. It works well, with one exception: I can't get the jQuery Dynatree to fill the lefthand DIV's horizontal space properly:

Here's the HTML:

<div id="sub-title">
   <div id="sub-left">
    <fieldset class="search-fields">
        <legend>Files Found</legend>
        <!-- Add a <div> element where the tree should appear: -->
        <div id="tree"> 
        </div>
      </fieldset>
   </div>
   <div id="sub-right">
     <fieldset class="search-fields">
        <legend id="selectedFileLegend">Selected File Contents</legend>
        <textarea name="fileContents" id="fileContents" rows="20" readonly="readonly" wrap='off'>
(select via tree on left)
        </textarea>
     </fieldset>
   </div>
   <div class="clear-both"></div>
</div>

and CSS:

#sub-left {
/*    background: #99FF99;  pale green */
/*    border:1px dashed; */
   float: left;
   width: 24%;
}
#sub-right {
/*    background: #FFCC99;  pale orange */
/*    border:1px dashed; */
   float: right;
   width: 73%;
}
#sub-title { 
    overflow:hidden; 
}
.clear-both {
   clear: both;
}

#tree {
  vertical-align: top;
  width: 250px;
}

I of course also use the dynatree CSS. Any idea what's wrong? Thanks for the help!

Answer 1

Your #tree width is set to 250px;

#tree {
  vertical-align: top;
  width: 250px;
}

If you set it to 100% (or remove the width property altogether), it will fill its container (#sub-left).

This is also the reason why it extends out of the #sub-left container when you have shrunk the window (second image), as 250px becomes larger than 24% of the available size.