6.5 Multiselection Of Elements In The Workbench

To change the attribute(s) of multiple elements (which are of the same type), select the elements in the workbench with your mouse while holding the shift- key (selects a range) or the command-key (adds another element to the selection). 

Now the shared attributes should be shown in the inspector and therefore any change of an attribute will be applied to all of the selected elements.

→ Use the sidebar to navigate.