The Action button appears as text like the rest of the items in the row. Suggest changing appearance either through a hyperlink or drop down indicator to show it’s clickable.
Also, the site is responsive with width, however on the Shared Documents page (on a desktop), it’s not as it requires a lot of horizontal scrolling and stretching of a browser window to see the Action area. You may be able to reduce the size of the Description field to allow for more text wrapping.