In 4.17 while in cascade, I was able to right click on ‘Distribution’, ‘Constant Curve’, ‘Uniform Curve’, ‘Points’ or the individual points in the detail panel and below ‘Collapse All’ and ‘Expand All’ there was ‘Copy’ and ‘Paste’. In 4.18 this is no longer the case. I don’t know if this was removed on purpose or not. Whatever the case may be, I really would like it to come back.
Should I post this as an issue in the issue tracker?
You should, been submitting quite a few bugs or reported weird “by design” things in cascade as of late myself.
cascade is near unusable on 4k monitors in 4.18.1 
Hmm, I just checked and copy/paste is still there for me in 4.18.1, just looking at a size by life module, vector constant curve. Might want to show some more specific examples? Because you’re right, it’s pretty essential.
I had a dig around and copy/paste has come back 
. It is only missing in weird cases. I can’t remember the curve I was attempting to copy yesterday but I have found a GPU particles module ‘Color Over Life’ with a similar problem. Its a ‘Distribution Vector Constant’, copy/paste exists when right clicking on ‘Color Over Life’ but its missing for ‘Distribution’ and ‘Constant’.
So It doesn’t seem to be missing consistently.
I’m working on a project that was recently updated all the way from 4.11 to 4.18.1 so maybe that’s part of the problem. If I can reproduce it in a new project I will report it as an issue.