I HAVE ONE QUESTION.........

Harry didn't die (though the horcrux in him did), and was therefore never defeated =)

recall that when Snape killed Dumbledore the wand wasnt his because they planned his death. The same goes for Harry, he planned on dying when he went into the forest therefor he was never defeated.

harry didnt die but the horcrux in him did so the elder wand was still his...

Harry never truly died. Nor was he Disarmed. Below I describe the passage of the wand since 1945.

Grindelwald Disarmed por Dumbledore, who was Disarmed por Draco Malfoy, who was Disarmed por Harry.

Note that in each of these cases, the anterior owner of the wand had been Disarmed. Through much of the Elder Wnd's history, its owners have usually been killed. However, you need only beat its last master to have true control.
In the forest, you may recall that Harry DID NOT, in any way, defend himself. Thus, their confrontation was not an actual duel, nor was Harry beaten. These little details make all the difference.

Remember, defeating a wizard does not just mean killing him. It could simply mean Disarming him.




On a side note, no witches have eve claimed to have the Elder Wand.

When Voldemort killed Harry he wasn't defeated because he had intended to sacrifice himself all along in order to save everyone, he didn't try to fight or defend himself.

Therefor when Harry was never defeated because everything that happened was according to plan, the wand recognized that and therefor didn't switch allegiances