Display::None propagation bug

[ickshonpe]

Bevy version

Main

What you did

Added red outlines to the innermost node of Bevy's display_and_visibility example.

cargo run --example display_and_visibility

1. Without Display::None set:
   

2. With Display::None set on the innermost node:
   

3. With Display::None set on the outermost node:
   

What went wrong

During layout recomputation if a node is found with Display::None set, that node and all its descendants are given a zero size.
This means most systems ignore those nodes since you can't mouse-over or draw inside a zero-sized element.

However zero-sized nodes can have outlines and outlines extraction only checks the local Display::None value for the outlined node and not the Display value of its ancestors. Which is why in 3 there is a visible outline around a UI node that should be removed from the layout and shouldn't even have a position to draw an outline around.