Dropdown menus are typically 'mouse-over and move mouse', not 'click-and-drag'

The original mac menus: click, hold, drag mouse to option you want, release mouse. Still works like that now, but the Windows-style click-release-move-click works too.

Combobox, then. They stay open once you click so you don't have to drag, but I've seen many users do the "click-and-drag" with it anyway.

Context menus are frequently touch-and-hold on touch devices.