SKLabelNode with Children not affected by gravity - not respecting zPosition - ios

Question

I have a wrapper class to create a label node with some subnodes. This is the init for the class:
let label = SKLabelNode(text: word)
let background = SKShapeNode(rectOfSize: size, cornerRadius: 0.5)
let mainNode = SKSpriteNode(color: color, size: background.frame.size)
label.horizontalAlignmentMode = SKLabelHorizontalAlignmentMode.Center
label.verticalAlignmentMode = SKLabelVerticalAlignmentMode.Center
label.addChild(background)
label.addChild(mainNode)
mainNode.zPosition = 1
background.zPosition = 2
label.zPosition = 5
self.node = label
In my main scene I instantiate the node, set its physics body and set the gravity for the scene:
self.physicsWorld.gravity = CGVectorMake( 0, -10 );
let node = MyNode()
node.node.zPosition = 99
node.node.position.y = endOfScreenTop
if let name = node.node.name as String!, let sprite = node.node.childNodeWithName(name) as? SKSpriteNode {
node.node.physicsBody = SKPhysicsBody(rectangleOfSize: sprite.size)
node.node.physicsBody!.mass = 1.0;
node.node.physicsBody!.angularDamping = 0.0;
node.node.physicsBody!.linearDamping = 0.0;
node.node.physicsBody!.friction = 0.0;
node.node.physicsBody!.affectedByGravity = true
node.node.physicsBody!.dynamic = true
node.node.physicsBody!.allowsRotation = false
}
addChild(node.node)
I have 2 problems:
The label appears behind the SKSpriteNode, even though the zPosition should place it at the front
The SKShapeNode (that's just an insets to smooth the corners) doesn't appear at all
None of the nodes are affected by gravity
PS. Even changing the following to true doesn't change anything:
skView.ignoresSiblingOrder = false
PS2. the MyNode class has these properties
var node: SKLabelNode
var speed: CGFloat = 1.0
var word: String
var color: UIColor
var kind: Kind

Answer 1

Assuming that skView.ignoresSiblingOrder = true in the view controller (the default setting), some thoughts...
When ignoresSiblingOrder is set to true, Sprite Kit ignores sibling relationships when determining the order in which to draw nodes. It does not, however, affect the parent-sibling draw order.
In either mode, the parent is drawn first and then the child nodes are rendered. Normally, the children appear on top of the parent (if they're at the same location) regardless of the zPositions of the parent and children! The exception is if a child's zPosition is less than zero. In this case, the child will appear beneath its parent (even if the parent's zPosition is less than the child).
It doesn't appear that you are setting node.node.name nor the name of the sprite node. If the names aren't set, the if condition will fail and the physics body won't be attached to node.node.
The default settings for shapes only draws a white border around its path (in this case, a rectangle). You should see this as an white outline around the sprite node. Setting background.fillColor = SKColor.greenColor() will show the SKShapeNode filled with green.