So, I've been able to disable the selection copy in Klipper. I have "ignore selection" turned on and that setting is working.

However, it's still frustrating that every time I delete a selection ( with the delete key) that creates a clipboard entry. Is there a way to make it so that only ctrl-c or ctrl-ins will actually copy to the clipboard?

In Klipper settings, what is set for General > Selection and Clipboard?

RIght now I have only checked:
Ignore Images
Ignore Selection


As far as I can tell, I have tried all combinations of the setting in Klipper before. Is this an X thing?

Can you please ensure that "Text selection only" is not checked?
As you suspect, this is quite possibly an X behaviour.

I can confirm that "Text Selection Only" is not checked. It is greyed out when "Ignore Selection" is checked.

Is there a way to control this in X? These days, I don't use an xorg.conf file anymore.

Unfortunately from what I can tell selection-copying is a hardcoded X feature which cannot be disabled. Klipper attempts to minimize the effects of this - however it seems that the feature is still working to a certain extent.

Ugh, stupid X. How far away are we, again, from Wayland?

It is likely to be a while unfortunately, as development on a Plasma based Wayland workspace is still underway.