This menu item is at the end of the menu sidebar. Clicking on the collapse menu will hide the textual representation of menu items and will display only the icons. When the mouse hovers over any of the menu item, the name of the menu item with the list of sub-menus displays.

Collapsing the screen, increases the size of the screen and lets you to do your work with more concentration.

In order to expand the sidebar, again click on the last menu item icons, which is a circle with triangle in it.