10 years later, 3rd party apps are still required for an actual middle click capability with the Magic Mouse (or any Apple Trackpad). Perhaps we will have to wait another 10 years for something built into macOS.
Until then, I have a couple more options to add to this list that I've developed (mind that they are not free).
Multitouch is an app for adding trackpad and Magic Mouse gestures to macOS, and middle clicking is one of the available actions that can be tied to a gesture.
Middle is a slimmer version of Multitouch, with the single purpose of adding middle click capability via a few select trackpad or Magic Mouse gestures.
In terms of free solutions, the mentioned open source MiddleClick app has been updated for Catalina in this fork: https://github.com/DaFuqtor/MiddleClick-Catalina.
My app, Middle, has a few key differences from MiddleClick-Catalina.
- It has built in settings for launch at login and hiding the menu bar icon
- It has a force touch gesture option for trackpad
- It has a “one finger in the center” gesture option for Magic Mouse
- Up and down parts of the click are synced with physical clicks instead of being executed after the up. This is important on CAD types of applications where you can pan using middle click.
I wrote Middle using Swift code from the mentioned Multitouch app. No code from MiddleClick-Catalina was used to build Middle.
It's also worth noting that MagicPrefs hasn't been supported in many years.
6I drooled over this mouse the first time I saw it, but without middle click, I have no interest in it anymore. – Peter Di Cecco – 2009-10-29T21:33:54.150
10To new people answering: please read the FAQ (http://superuser.com/faq). This is not a forum, this is a place to provide answers to questions. Avoid posting answers with only your personal opinion. – Gnoupi – 2009-11-04T10:02:38.647
13Guys, it took them 20 years to put a right button on their mice-- give them time. – MiffTheFox – 2009-11-09T20:49:50.967