Workspace InfoObject
The Workspace InfoObject has a special position among other InfoObject types:

Working with the Workspace InfoObject
Opening a catalog or an editor (from the Sidebar (A) or a Smart Tile) automatically creates a new tab in the Workspace with the object opened.
To close an object opened in the Workspace, use the cross symbol at the right of the window tab. (B)
Depending on the window content, use the OK/Cancel/Exit buttons at the bottom of the editor or catalog to leave the window with or without saving the changes. (C)
Use the icon in the top left-hand Workspace corner to close all catalogs and editors opened in the Workspace with a single click. (E)
Use the 'Maximize' icon (D) in the top right-hand Workspace corner to maximize the Workspace while temporarily hiding other InfoObjects in the perspective.
When maximized, use the alternative top right-hand icon to restore the Workspace to its original dimensions.
Note the absence of the top right-hand icon for closing of the entire InfoObject: As the Workspace InfoObject is the default InfoObject for the Work Page perspective, it cannot be removed.
See also Adjusting InfoObjects and InfoObjects Positioning for Workspace geometric adjustments in relation to other InfoObjects.