[Moving image/selection from one open tab to another]

Hi Willie,

I too understand the painpoints as a lifelong Photoshop user moving slowly into affinity full time.  
So to accomplish this I do the following:

-ensure that your selection is on it's own layer.
-I have two monitors so I can have both the selection image document open with it's layers dialogue open next to the new receiving document.  with this arrangement I simply pull the layer onto the new document which is open right next to the original image selection layer.

I pull the layer onto my new document.  works good.