The mouse cursor gets centered in the screen any time a shulker is opened in inventory. This is very annoying.

Desired behavior: when opening a shulker in the inventory, the mouse cursor remains at the same place.

This is a tough one I've been having issues with for a while. Problem is vanilla by default resets the cursor to the center when a new screen is opened. I'll have to keep looking for a work around

Could you just save the cursor position when clicking and restore it after the box opens?

I have fixed this, releasing on curseforge soon