I have a layout in progress I'm working on, but the background disappears in Firefox when I try to use floats for a 3 column layout. The page appears properly in IE, but not Firefox. See the gray background and dotted borders are supposed to enclose the leftct and rgtct divs. When I use float:right on the rgtct div, the background in wrapper div disappears. The site in question can be found at:
http://leaf.mreh.net/community/

The css for the site can be found at: http://leaf.mreh.net/community/comm.css

I tried to do the site another way, using a backgound color and borders in leftct and rgtct to get the same effect. Only I found that the effect wouldn't cover the entire height of the layout, and I have no idea how to get it to do that. I'd prefer to get the background to work somehow, but if that's not possible, maybe someone knows how to extend the height in my second attempt? Examples of the alternate method I tried are below.

http://leaf.mreh.net/community/index2.html
http://leaf.mreh.net/community/comm2.css

Any help with this would be appreciated. Thanks.