The functionality of the buttons is working fine when I test it in Safari on the Mac. Are you talking about the outline when you click on the button that appears larger than the actual button? The guy who worked on the Spry Widget Slideshow says that you can turn off this by specifying outline : none; in the css.
I am having the problem that you mentioned in Firefox. The slideshow works fine but when you hover over the left arrow you get a dotted 1 px border that goes about 800 px wide and 400 px high, if happens again if you click on the right arrow. I went throught both the internal css and external and I just can't find that code that you mentioned (outline : none;tline). Could you help?
P.S. I didn't see this problem in IE