Unreal Engine 5.8 UI/UX — UMG and Slate, CommonUI, the 5.8 Unified Input System (Enhanced Input + Common Input merged), gamepad/cardinal navigation and focus, DPI scaling and safe zones, widget performance (invalidation, retainer, volatile, bindings), and UI debugging. Use when building or reviewing HUD/menus/tooltips, wiring gamepad or multi-platform input for UI, fixing focus/navigation/layout/scaling issues, or when UI is costing frame time.
