If you need to add more css and customization options to the Default WordPress Category Widget this plugin is for you. Using this plugin you can display your sidebar categories in a tree-view in just one click. Features The selection state is preserved (the parent category remain open) Fully customized and easy to use Display as dropdown or tree-view Dynamically create your website tree for all posts & categories Ability to hide/show count Ability to hide/show child When a child is selected The parent category is also selected