Inspector insert box when clicked closes so fast on Mac

I am using cubase 12.0.52 running on Mac OS Big Sur. I am having hard time with the bugs in both cubase and Nuendo at the inspector section. I am not able to add any inserts since the insert box when clicked shows the list of plugin page but it closes so fast that you can’t even select anything. Also we can’t make any changes to the routing in mix console window due to same issue. Anybody experiencing similar issue? The same issue is there in Nuendo as well.

I had a similar problem some months ago on Windows. Replaced my mouse, issue is gone.