Suggestions to improve

It works fine and does what it says.
I have 2 suggestions: if the sliding tab is used left or right, add an option to alter the height.
And maybe a nice one could be adding opacity to the tab.

Almost forgot: will there be an update soon? If so, please add a repair for the upside down tab in Internet Explorer.

http://wordpress.org/extend/plugins/wordpress-sliding-drawer-content-area/