Most of the time I just want preset DSP Chains to add to a certain DSP chain I already have instead of switching them.
How do I do this without needing to make an extra track and copy-dragging each unit?
Preferences -> Files - Untick Replace Existing Chain in the Device Chain Import section.
Roughly in the middle.
Thanks! 
As you may see, there are couple of shortcomings in the approach devs have taken.
Modulation devices apparently have relative bindings. If a chain is loaded that contains modulation device which modulates trackvolpan device it must be loaded to beginning of the chain, or the linkage is lost. So it may be necessary to adjust the modulation destination if there is already devices present in track fx chain, since one cannot choose what part of the fx chain devices are loaded into.
Also because of previous point and the fact one cannot select and move multiple devices around simlutaneously it can be painstaking to rearrange complex chains that are loaded to the end of the track fx chain. This means extra work that could have been avoided if these things would have been addressed in the first place.
Plus one cannot choose whether to add or replace when loading, so one is basically stuck with one method unless willing to change preferences every time another one is wanted or needed.
e_typo
If the device is modulating other devices within the chain, then the relative bindings should be preserved. I’ve just tested this myself with a few LFO and Hydra setups and it seems to be working normally.
There does indeed seem to be some strange behaviour if the chain you import controls the track properties. Will try to look into this.
Yep. I agree with you here - moving several devices at once can be quite a pain. I’m sure this will eventually be addressed somehow.
Right-click the .xrnt DSP Chain preset in the Disk Browser, then choose “Load File with Options”.
all cool, thanks for clearing this up all of you!
Aha, nice! 
I meant that if the device is outside the chain being loaded. I see references are numerical, and trackvolpan is referred as 0.0, which has been previous effect meaning trackvolpan, but when loading options were introduced the positions became relative rather than absolute. It would be super if one could refer to devices outside the chain loaded by device name, so if one has somewhat static channel setup he could skip the phase of setting modulations up every time. Will have to be thinked over.
Will have to wait for that.
I have totally missed this. More intuitive ways would be drag and drop and/or just separate “add” and “replace” context menu entries. It is already possible to select a device, so it would be logical to place the loaded chain after the one that is selected.
Thanks for new totally useful information.
e_tidying