3 Column CSS Layout - Resizeable Controls?

[The_Grudge]

I've setup a 3 column layout for my web page using CSS. The page works well, and when I increase/decrease the width of browser window, the columns shrink accordingly, as I have a percentage assigned to each column width.

The problem is, I have controls within each column (or div). How do I make the controls grow/shrink in width whenever the browser window is made smaller or larger?

For example, in my left column I have a listbox control. When the browser window is adjusted to be more narrow the three columns shrink in width, but the listbox control stays the same size, so it encroaches on the middle column.

Basically, I'm trying to make the page grow/shrink based on the size of the browser window. The columns do, but the controls are the same size. When I try to set the width of a control using a percentage, it takes that as a percentage of the entire page, and not the <div> that contains the control.