/// <summary>
/// Updates whether this <see cref="SelectionHandler{T}"/> is visible.
/// </summary>
private void updateVisibility()
{
// fix the case that only selected blueprint in current handler can show selection box.
// todo : this is the temp way, might remove after official fix that.
bool visible = containsSelectionInCurrentBlueprintContainer();
SelectionBox.FadeTo(visible ? 1f : 0.0f);
}