Fix scale factor bug

[nixonyh]

• Double down on the builder method for widget creation

[Sheerwin02]

Looks good to me.

Just that when I go through, since currently widget have pub children: Vec, so in the future if remove a node from the tree need to remove it from the widget's Vec too, cause I suspect if a node is removed from the Rectree using tree.remove(), the parent widget's Vec in the World will still contain the deleted NodeId.

[nixonyh]

Just that when I go through, since currently widget have pub children: Vec, so in the future if remove a node from the tree need to remove it from the widget's Vec too, cause I suspect if a node is removed from the Rectree using tree.remove(), the parent widget's Vec in the World will still contain the deleted NodeId.

True, but there's no use case for it in this example, similar to when u did yr PR, it wasn't implemented too because it won't/can't be used due to lack of interactivity.

[Sheerwin02]

Looks solid for an example!