In document, there are two ‘style’ options of UI layout - Anchor and Dock.
But there is only a style for anchor.
There is another mention of dock layout for UI, not certain it is compatible with ‘anchor - stretch’.
Document needs to be updated to properly explain what ‘Anchor Presets’ / Anchors values and removed ‘Dock Style’ in current editor are.
And there are some more undocumented logics with UI layouts.
i.e : values ‘Right’ and ‘Bottom’ in Transform acts like pixel coordinate when ‘Anchor Presets’ are ‘Top/Bottom/Left/Right etc’, but acts like UV(0~1) when ‘Anchor Presets’ are ‘xx Fill etc’.
