drawpile
Selections: present floating pasted images in the layer list
Pasting an image should show a temporary pseudo-layer in the layer list, which you can either merge or create a new layer out of (or, if it's implemented, create a reference image from it.)
This should also extend to the transform tool.
When you transform a selection, it should prompt whether to merge down or create a new layer for it,
however the default double-click away action should result in merge down.
Better yet, while the temporary layer is active, it should allow you to brush in the empty space resulting from the transformation.
This feature can also be used to facilitate the workflows that are awaiting #1328 (loading or pasting as new canvas).
This feature (#1266) involves loading or pasting an image as a hidden client-side floating layer (movable in the layer list) which can be confirmed to exist as separate layer, or pressed down into the layer below itself.
However, through some adjustments of this (floating layer) feature, we can also allow users (especially on mobile) to do much of the operations requiring #1328. This involves implementing auto-adjustment of the canvas size to match the floating layer, when done on an empty canvas, and perhaps, even a prompt to "add as new layer or flatten AND adjust canvas size" locked behind a permission,
This will be especially useful for mobile users, and serves as an alternative pipeline.