Joao Silva

Well.. ignore the question. This can be achieved by using the alignment options as seen on the image... and mentioned on here
 

Humm... just found on reddit.. that if the objects are placed inside each other.. the bigger one is considered as "key" object. Well.. after a few tests i confirm that it does work like this. But.. what if i want it the other way around? Or if all objects are of the same size? Is there any documentation on this?

No.
I wish there were a way but there isn't.
What is as bad or worse is that we can't even use Guides or some other object to snap the handles to. The handles won't snap to anything that I can see. Please see Hangman's correction. I am happier now.

Well.. try to replicate this. Apply a live filter like distortion to an object (let's say... a dotted XoY plane).. then.. scale this object after the live filter has been activated!
 
Artifacts should be poppin like..  leprechauns at the end of the rainbow...
 
As far as i can see.. it seems to me like the yser-invisible mesh used for the live filter is not updated with the upscale or downscale of the object resulting in this (gaps, distends or overlaps). This seems like a core error.. not a graphical card issue.. but.. i might be wrong..
 
This however does not happen on the newest beta. So.. they probably fixed this scaling issue already. I will be using the beta a checking for further errors...

Well... you know what?!.. It actually improved the performance and those live filter bugs vanished!
I did uninstalled everything and executed "Advanced Uninstaller Pro 13" to remove all traces of the old DLLs and registry signs (the free version works fine for this). After the re-install and after downloading everything again.. well.. the old afphoto files that were "spitting in the soup" (old saying here) ... no longer "spit on the soup" .. and to be quite honest.. they seem to "like the soup" very much now!!!

The Affinity photo was even sluggish on a 200 MB file (and that never happened before).. and now it seems fine again!
 
For now.. it seems to be working much better! I would advise you guys to try it.. it takes just a few minutes to do it.. so.. why not?