widget display

My site is http://avelim.org.il/

I have a questions regarding widget display:

My site has 3 drop down menu widget on the top left, That are created by your plugin.
Each widget has a different length. I want them all to be the same length. How do I achieve that?
See
http://goo.gl/X3CMt

http://ww.wp.xz.cn/extend/plugins/extended-categories-widget/