Put .dropdown-trigger on the control that owns the menu — it declares the anchor the menu positions against. Items reuse .command-item so menus and palettes stay consistent.
<buttontype="button"class="button secondary sm dropdown-trigger"popovertarget="doc-dropdown">Actions</button><divid="doc-dropdown"popoverclass="dropdown"><buttontype="button"class="command-item">Duplicate</button><buttontype="button"class="command-item">Archive</button><buttontype="button"class="command-item">Delete</button></div>