Customizing format toolbar

I just installed 3.5.5 on my Mac. In Writer, the downward facing arrow does not appear at end of the toolbars (standard and format) so I can’t add/ remove buttons.
Is there a solution to this problem

That arrow shows when there are more buttons on the toolbar. Can you right click the toolbar and select “customize toolbar”?

… or Menu “View” → “Toolbars” → “Customize...”.