Node-tree 'Actions' can't be applied to other nodes?


Let’s say you have a Color ‘MixRGB’ node, and you animate the Fac slider to go from ‘0’ on Frame1, to ‘1’ on Frame3.

This will appear on the NLA Editor, it will also appear in the Outliner under ‘Blender File’ / ‘actions’.

But you cannot add this action to other nodes with a Fac input because it does not appear in the Action Editor’s ’ ‘Browse Actions to be linked’ dropdown, nor the dropdown in the NLA Editor under ‘Animation Data’.

Why do Actions (which ARE listed as Actions under ‘Blender File’ / ‘actions’!!!) NOT appear in the these dropdowns for applying Actions to new things?

Is there a way around it?