To toggle the sidebar, click on the i icon next to the collapse and close icons.
You can currently modify the width and the background color of the box sidebar. The startOpen argument allow you to control if the sidebar should be opened or collapsed at start. The box sidebar works very well to embed inputs elements such as slider inputs, as in the example above. Never use the sidebar when the box body is empty, since the sidebar height depends on the body height.
Notes
When including an image in the box sidebar and to make sure it is correctly displayed, you have to add a style attribute to the img tag as follows: