Child fieldsets don't clear their parent in IE

On the /control_panel page, if I have an incomplete row of icons and a child panel, the child panel will appear on the last row of icons, rather than immediately following it in Internet Explorer 6.

To solve the problem, I added a class to the fieldsets in the module, and added "clear: left" for that class in controlpanel.css.

I'm sure that this is a problem with Internet Explorer, rather than the module itself, but the workaround is standards-compliant, as far as I know, and makes things look a whole lot better in that browser, without changing its appearance in Firefox (I don't have any other browsers with which to test it).