Copy-paste of keyframes is now slot-aware. See [1] for the design.
[1]: https://developer.blender.org/docs/features/animation/tools/action-editor-copy-paste/
In short:
- Copy-paste still works broadly as it used to. Only the visible
F-Curves are pasted into.
- Slot identifiers matter when copying from multiple slots. When
copying from one slot, they don't.
- Selection of channels (either F-Curves or Slots) determines where
keys get pasted into.
- Pasting will either copy from the slot with the same identifier
(when identifiers matter), or paste whatever was copied (when they
do not).
- If both F-Curves and slots are selected, only the selected F-Curves
get pasted into, and slots without any selected F-Curves are ignored
(i.e. target is only defined by selected F-Curves, or only by
selected slots, never by a mixture).
Fixes#129690
Pull Request: https://projects.blender.org/blender/blender/pulls/133979
2b5946da4e