The show "More" / "Less" button in the facets is causing browser issues. The facets are displayed in a dl list, but the "More" and "Less" links are just inserted into this dl list as divs and spans ( without dd tags ). Also it seems these tags are not closed properly in some situations ( depending on how the facets are being ordered and displayed )
This causes this expansion feature to act a bit unpredictable on different browsers.