CMD + Double Click in finder to open in new tab help

Hi all, I'm trying to make it so when finder is focused, clicking the middle button on my mouse will register CMD + Double Click to open the folder in a new tab. I'm attaching a screenshot showing what I've done. But it doesn't seem to work, am I missing something? Thanks in advance!

Update: I've just noticed that I can't change the behaviour of middle click at all. It seems that my original issue is not connected to the action I'm trying to make work but a more fundamental one. I'll create a new topic and if I find a solution I'll also update here.