# Objective
1. Nodes with `Display::None` set are removed from the layout and have
no position or size. Outlines should not be drawn for a node with
`Display::None` set.
2. The outline and border colors are checked for transparency together.
If only one of the two is transparent, both will get queued.
3. The `node.is_empty()` check is insufficient to check if a border is
present since a non-zero sized node can have a zero width border.
## Solution
1. Add a check to `extract_uinode_borders` and ignore the node if
`Display::None` is set.
2. Filter the border and outline optional components by
`is_fully_transparent`.
3. Check if all the border widths are zero instead.
## Testing
I added dark cyan outlines around the left and right sections in the
`display_and_visibility` example. If you run the example and set the
outermost node to `Display::None` on the right, then you'll see the that
the outline on the left disappears.
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