Strange IE6 bug - show/hide select, hemorrhage option innerHTML

We've all had to code up those ever-so-fun branching selects. I chose to implement it by showing or hiding (display:block/none) the container of the label+select corresponding to the appropriate branch. And IE6 decided to hemorrhage option innerHTML onto the page - for 1 of the 3 branches: the middle one. I solved it by adding "position:absolute" to the css for the container.

Some cross-browser findings

ff2 mac: doesn't understand floating-point percentages (ie: 107.3% = 107%) - ran into this with font sizes.

ff3 thinks that if your parent is visibility:hidden, but you are visibility:visible, that you should display. (wrong.)

IE8 VHD from microsoft on vpc2007 is not the same as ie8 in the wild. Button element widths seem to be at least 1px wider in the wild.