EnsureVisible doesn't' selects/focus node, it only make it visible in the viewport/FlyGrid. To select this node use:
[C#]
private void EnsureVisibleandSelectNode(FlyGrid flyGrid, NodeBase nodetoEnsureVisible)
{
flyGrid.ActivePort.EnsureVisible(nodetoEnsureVisible);
flyGrid.Selected = nodetoEnsureVisible;
}