Macs & Gramps tools that use 3 mouse buttons

While doing an update to the Gramps keybindings wiki page, I noted the caveat about using the Ctrl-Click with the macOS single button mouse where right-click is needed for a Gramps feature.

But I’ve been running into more Gramps features that use the center/middle button of a 3-button mouse. (Such as: setting a zoom rectangle in the Geography view; or, frequently used configuration options in the experimental CardView Addon)

How do macOS users do a “center-click” (or drag)?

With my Mac, I have a two-button mouse with a center wheel (something generic brand, not Mac-specific). I find that I can use the center wheel to click and drag to set a zoom rectangle in the Geography view. I haven’t tried the options in the CardView Addon.

An aftermarket mouse seems like a good idea. (despite Steve Jobs’ button phobia)

But the goal of this question is to discover info. Either to add the macOS center/middle button keyboard equivalent among the Keybindings page’s hints. Or to make certain critical features are not uniquely offered in the interface somewhere that cannot exist cross-platform.

Note that a considerable number of Mac users have a trackpad rather than a mouse. See the following for a complete list of actions available:

Now we need to figure out what GTK3 does with those inputs!

Craig