Sometimes Command+Click will open in a new tab when Middle Click doesn't work, and sometimes Middle Click will open in a new tab when Command+Click won't work.
If you're using Gmail, you get both types of behavior on the same page!
Isn’t middle click a user defined function? Is it system defined? I assume you could assign ctrl/cmd-click to the middle button if you want. I’ve not worked on a system with a middle mouse button in many years.
I haven't owned a mouse without the ability to middle click ever (my first mouse had a ball and 3 buttons; I think a Logitech c7?).
If your mouse has a scroll-wheel, then it's probably clickable as a middle-click. If you have a trackpad without a 3rd button then there is usually a gesture that will send a middle click.
