Removing Extra Space when CSS 'float' is used

I am unable to remove the extra space above 'Smart Filter' in the div id='container_sidebar', this example posted on fiddle http://jsfiddle.net开发者_开发技巧/XHPtc/

Seems like if I remove the float: right property of that div 'container_sidebar' I will remove that extra space above but obviously that will destroy the layout. Any idea what may be the bug?

Remove margin-bottom: 20px; from #searchresult_filter_box CSS.

problem is in searchresult_filter_box

you have bottom margin of 20 px there

To find out I used Inspect Element in Firebug, similar result you can see in Opera (but the jsFiddle looks like a useful thing, I didn't know that one)