contextMenuEnabled property
Whether right-click (desktop) and long-press (touch/stylus) open a context menu. When false, selection, link taps, and pan/zoom still run normally; only the popup menus are suppressed. Defaults to true.
This covers the desktop right-click text menu even without editing (reader mode), plus - when editing is set - the right-click and long-press annotation menus. It also hides the floating touch selection chip (Copy / Select all / Markup) entirely; the selection itself and its drag handles stay, so the host can offer those actions in its own chrome. The long-press annotation menu requires editing; the desktop text menu does not.
Implementation
final bool contextMenuEnabled;