Overflow: auto + float: left cause problems?

[aherrera]

Has anyone ever had any trouble with divs inside a container div that has overflow set to auto? I'm working on a client project and whenever I use a float, the container div expands instead of staying at the height I specify and showing a scrollbar. I'm stumped.

Here's some basic sample code...

HTML:

<div class="container">
   <div class="left">...</div>
   <div class="right">...</div>
</div>
...

CSS:

.container {
   width: 100%;
   height: 150px;
   overflow: auto;
   ...
}

.left {
   width: 35%;
   float: left;
}

.right {
   width: 60%;
   float: right;
}

[stoavio]

Setting the overflow to auto will allow the box to expand when the content contained within the bounding box of the block-level element extends beyond the dimensions of the box.