How to disable right-click pop-up menu in Pages Dock?
In order for recent items not to show on an application's dock tile, you'll need to do at least two things, as also shown in the images below.


First in System Preferences > General, set e.g.: Recent items: 10 Documents, Apps, and Servers to : Recent items: None Documents, Apps, and Servers
Next, In Pages, as well as other apps that have an Open Recent menu item on the app's File menu, click Clear Menu in order for them not to show after taking the first step.