I'll try to explain the question as best as I can, for those who are still confused about what really happened with the Elder Wand:
When Draco disarms Dumbledore on the Astronomy Tower, the actual Elder Wand doesn't go to Draco (it stays with Dumbledore in his tomb), but the power does go to Draco's wand.
"The Elder Wand recognized a new master before Dumbledore died, someone who never even laid a hand on it. The new master removed the wand from Dumbledore against his will, never realizing exactly what he had done, or that the world's most dangerous wand had given him its allegiance..."
When Harry gets the Elder Wand from Malfoy, he gets the wand with the Elder Wand's power.
Voldemort takes the original wand from Dumbledore's grave- but that doesn't give him the actual power of it.
"I stole the wand from its last master's tomb! I removed it against the last master's wishes! Its power is mine!"
"You still don't get it, Riddle, do you? Possessing the wand isn't enough! Holding it, using it, doesn't make it really yours."
So Harry disarms Voldemort, and gets the original Elder Wand- as the ex-Voldemort wand, and the Elder Wand's power as the ex-Draco's wand.
Now that Harry has both wands, would the "power" recognize the "original" wand and reunite with it, leaving Draco's wand powerless?
I would think that the wand wouldn't reunite with the power, because the wand's owner didn't defeat the owner of the Elder Wand's power.
But then Harry mends his wand with the Elder Wand, and it seems as if the Elder Wand got it's power back.
He laid the broken wand upon the headmaster's desk, touched it with the very tip of the Elder Wand, and said, "Reparo."
So what's happening? Why would the Elder Wand's power go back to the Elder Wand itself?