When applying the "Bake Action" operator in pose mode
it could throw an error saying "Nothing to Bake"
even though bones are selected
That is because the code was looking for a selected armature
But in Pose Mode, clicking into empty space to de-select would also
deselect the armature.
Then box selecting would not make the armature selected again
Reviewed by: Sybren A. Stüvel
Differential Revision: https://developer.blender.org/D16593
18de712257
