Seems to be a bug with the sampler not respecting these options when dragging .xrnt presets from the “Other” tab in diskop:
So with this options enabled, dragging overwrites the present chain in sampler. Works as expected on main tracks in pattern ed/mixer though.
While on the subject a small request would be that when you drag .xrnt into renoise, that you would be able to place/insert them at any point in the chain - same as for normal loading of fx from the left-hand fx chooser.
related thread:
Organising Your FX