bottom border mis-alignment

there seems to be a mis-alignment at the bottom border of the sidebar names and the arrow. I don’t see it in appearance>widgets, i only see it in the page widgets created by the plugin. I tried comparing styles of wp’s widgets and your plugin’s widget page, but i can’t seem to pinpoint the cause for the mis-alignment. Hope you could help me with it.

thank you for the awesome plugin.

http://wordpress.org/extend/plugins/wp-page-widget/