There is nothing outside the TD except a TR.

I tried to make a demonstration by replicating the entire TABLE and the element structure in the TD where I had the disappearing content, and the applicable CSS but I could not recreate the problem.

Depending on some variables, the image may be hidden via display:none, and in it's place a text input and button, or vice versa.

The javascript in question does work in IE so it's not a problem there, and in the original document where the problem occurs, I can 'turn' the problem on and off by toggling position:relative on the elements inside the TD.

If I have time I will try to investigate it more but for now I will just leave it at this:
If you have the disappearing content bug in IE but not FF, I can say from experience that one possibility is position:relative on the elements in question.

I was going to post some code, but posting partial code will lead to "post all the code" and that would lead to "why do you do this or that", etc. and it would get way off topic.
This is in a web application I developed for a company I work with for backend database management for their websites, and the code in total is over 12,000 lines, of course not all of it relates to the problem, but the main doc and JS represents a huge chunk since the application uses AJAX and is only loaded once per session.

If I find I can replicate the problem outside of my application I will post a demonstration, I do believe that it is not position:relative all by itself causing the problem, just one contributing factor.

EDIT: I do want to reiterate that as large as my document and css are, the CSS validates error free, the HTML DTD is "HTML 4.01 Strict" and also validates error free, I use HTML 4.01 since IE doesn't support XHTML and parses it as HTML.