At one point I used to be able to right-click a word in my project and the context menu would offer me my installed Chambers Thesaurus. I wish knew how I did that, it doesn’t work after 3.x and I have no idea how I did that in the first place. Any ideas? Thanks!
It is typically up to the utility program to insert helper commands into the contextual menus of other programs, like Scrivener. In the past there were certain techniques for doing that which have over the years been deprecated. It could be whatever they were using no longer works with the newer Scrivener framework. I would check and see if they have any updates to the software that might rectify that, or if not, a Service (check in System Preferences: Keyboard: Shortcuts: Services) that can be enabled and optionally assigned to a shortcut.