Background Image and Form Problem

I've created a fairly long form (http://www.elviowebdesign.com/proposal.html) to gather information about the services my clients need for their websites. However, when I click on the Proposal Request link in my left sidebar the background image that I applied to my body tag temporarily replaces the left sidebar and the margin between the left sidebar and main content area.

This occurs while using Firefox 1.5.7 or Firefox 2.0 and only on the Proposal Request page that contains a form. In Netscape 8.1.2 the background image completing over rides the entire page when I click from page to page. When I shorten the length of the form so that it is less then the height of the sidebar the problem disappears in Firefox. Please note that the Proposal Request page works fine in IE6 and Opera 9.01

To replicate this problem click on all of my left sidebar links several times including the Proposal Request link.

I've tried the usual fixes like clearing my cache and reloading my browser.

The CSS for the site is located at:

http://www.elviowebdesign.com/elvio.css

How can I fix this problem so the background image doesn't over ride my sidebar and margin when I click on the Proposal Request link in my sidebar?

The issue seems to be related to incremental rendering, as opposed to any type of override or replacement; incremental rendering allows a page to be displayed before it has fully loaded. Being that I’ve tuned my incremental rendering setting so that pages load faster than the default, I see this on all of your pages. I’m guessing that the effect is related to the non-linear way that the page is constructed; the navigation comes after the content in the document source.

Before the navigation has loaded, nothing is shown in its place, allowing the body element’s background to show through. Since the page with the form elements has the most code to process, it wouldn’t be surprising if the navigation on that page took the longest to load, making the effect more likely to be noticeable. I would guess that the solution is to either linearize the source code or to apply a background that matches the layout background (white) to the layout container.