Why is "create snapshot (ghosts)" disabled? (baked sound F-Curves in Graph Editor) In VSE I have inserted a sound clip and added two custom properties.
This is purely so I can bake different frequencies as F-Cruves which greatly helps with aligning video with music.

I want those two F-Curves to be always visible in the Graph Editor. There seems to be an option that should do exactly that. In Graph Editor on the bottom bar (with menu) at the very end there is a button with a ghost icon (a second one in that row, first one is to show channels from not visible objects) that has a tooltip saying:


  Create snapshot (Ghosts) of selected F-Curves as background aid for active 
  Graph Editor bpy.ops.graph.ghost_curves_create()


However this button is disabled and there is no indication why.
I have my sound clip selected, with two custom properties keyed and F-Curves for those selected.

How do I make snapshot of those baked sound F-Curves?

P.S. If it makes any difference I have Blender v2.77
The button you are after I believe is on the left of the ghost button.

Graph editor with 16 channels baked to sound to custom properties AA0 - AA15


Click on the cursor button (show_only_selected = False)  and it wont matter if the object you have baked the fcurves onto is selected or not.



Lastly I've added AA9 to the search field, and filtered to only show Speaker animations.  Now that is all this graph editor will display. If I used "AA1" as the filter string it would show AA1, AA10 ... AA15.  



The BGL overlay is from my Sound Drivers Addon and can be drawn on top of graph editor, 3D view and timeline.