# Objective
During the migration to required components a lot of things were changed
around and somehow the draw order for some UI elements ended up
depending on the system ordering in `RenderSystems::Queue`, which can
sometimes result in the elements being drawn in the wrong order.
Fixes#19674
## Solution
* Added some more `stack_z_offsets` constants and used them to enforce
an explicit ordering.
* Removed the `stack_index: u32` field from `ExtractedUiNodes` and
replaced it with a `z_order: f32` field.
These changes should fix all the ordering problems.
## Testing
I added a nine-patched bordered node with a navy background color to the
slice section of the `testbed_ui` example.
The border should always be drawn above the background color.
a949867a1c