Category Title Alignment in Search Form (IE8)

I am using Simplemap 2.3.1. I noticed that when I add categories the search form appears differently in IE8 and FF. In FF, the categories align one on each “row” and stack on one another. Like this:

Category 1
Category 2
Category 3

However, when viewed in IE8, the categories align one after another in the same row. Like this:

Category 1 Category 2 Category 3

This causes any category after number 2 to be hidden underneath my two sidebars. The Search form doesn’t seem to respect the boundary of the post in this instance.

Also, in both IE8 and FF, it seems that the more categories added causes the states text box to shift to the right, sometimes significantly.

My main question is how do I get IE8 to show categories as FF does? Having them in a vertical line doesn’t work for my purposes as I will have between 5-7 categories.

Thanks!