Which context menu the viewer would show, based on what was right-clicked: the page background, a selected object, a text editor, and so on.
Bitmask of ContextMenuOperations flags describing what is allowed for the current selection — use it to decide which items of a custom menu to enable. The same mask drives the enabled / disabled state of the built-in menu items.
Click position relative to the document render element.
Data passed to IContextMenuRequestedCallback when the user right-clicks (or long-presses) inside the document and the viewer is about to open a context menu.