void AddSequence()
{
SequenceNodeEditor seqNode = CreateInstance <SequenceNodeEditor>();
seqNode.nodeRect = new Rect(mousePos.x, mousePos.y, 120, 50);
bt.nodes.Add(seqNode);
AssetDatabase.AddObjectToAsset(seqNode, bt);
}
void AddSequenceChild()
{
SequenceNodeEditor seqNode = CreateInstance <SequenceNodeEditor>();
seqNode.nodeRect = new Rect(selectedNode.nodeRect.x, selectedNode.nodeRect.y + (selectedNode.nodeRect.height * 2), 120, 50);
bt.nodes.Add(seqNode);
selectedNode.AddChild(seqNode);
AssetDatabase.AddObjectToAsset(seqNode, bt);
}