I was sick of continuously searching for things to hold my curtains back. So I signed onto the interwebs and whipped this up using Onshape. It's has massive tolerances in the hinge so that it could work with 500um z wobble, which I am currently struggling with (egh).

Nevertheless, I hope this helps you with your curtain management predicaments.

My settings: 100um layering Rafting - 2 layers Support - None

Also: If it isn't latching shut, try lining the hinge and latch length ways with the curtain, the outwards force helps hold the latch shut.