git:20260302.11fee6c to git:20260303.768e90e

80 added, 8 removed. Audit A to A.

---

name: ue5-ui-umg-slate

description: UE5.6/UE5.7 UI development workflow using UMG and Slate integration. Use when requests involve Widget Blueprint setup, Slate host widgets, lifecycle binding, input and focus handling, tooltip behavior, or viewport clamping logic.

---

# Quick Start

- Identify whether feature belongs to UMG, Slate, or hybrid bridge.

- Define data source component/subsystem and UI binding point.

- Output widget tree intent and runtime binding sequence.

+ # UE5.7 API Anchors

+ - UMG lifecycle and viewport anchors:

+ - `UUserWidget::NativeConstruct()`, `UUserWidget::NativeDestruct()`

+ - `UUserWidget::AddToViewport(...)`

+ - `UWidget::RemoveFromParent()`

+ - `UWidget::SetVisibility(...)`

+ - `UWidget::SetKeyboardFocus()`

+ - UMG input mode anchors:

+ - `UWidgetBlueprintLibrary::SetInputMode_UIOnlyEx(...)`

+ - `UWidgetBlueprintLibrary::SetInputMode_GameAndUIEx(...)`

+ - `UWidgetBlueprintLibrary::SetInputMode_GameOnly(...)`

+ - UMG/Slate bridge anchors:

+ - `UWidget::TakeWidget()` for Slate bridge hand-off

+ - `SCompoundWidget`, `SLATE_BEGIN_ARGS(...)`

+ - `FSlateApplication::SetKeyboardFocus(...)`, `SetUserFocus(...)`

+ - Viewport geometry anchor:

+ - `UGameViewportClient::GetViewportSize(...)`

+ # UI Stage Contract

+ - Every UI task must define:

+ - UI layer ownership (UMG-only, Slate-only, or hybrid bridge)

+ - data source and update trigger (pull, push, event, or mixed)

+ - focus and input ownership transition

+ - viewport-safe placement behavior for tooltip/popup

+ - teardown/cleanup path for unbinds and widget removal

+ - If any item is missing, the UI implementation is incomplete.

# Workflow

- - Create or update UMG widget and required exposed variables.

- - Build Slate widget when custom grid/input rendering is required.

- - Bridge UMG and Slate through a host `UWidget` wrapper.

- - Bind runtime data on construct/init and subscribe to change events.

- - Handle focus, visibility, and tooltip screen-edge clamp behavior.

+ ## 1) UI Architecture Decision

+ - Select UMG for standard game HUD/menu work.

+ - Select Slate for custom rendering/input behavior that UMG cannot express cleanly.

+ - Select hybrid when a `UWidget` host needs to embed custom Slate content.

+ ## 2) Construct and Lifetime

+ - Initialize widget bindings in construct/init path.

+ - Register event listeners once and store handles when required.

+ - Define destruct/unregister logic explicitly to avoid stale bindings.

+ ## 3) Data Binding and Refresh

+ - Bind runtime data from one authoritative source (subsystem/component/view model).

+ - Use event-driven refresh for high-frequency data where possible.

+ - Keep display widgets read-only for gameplay state mutation.

+ ## 4) Input and Focus Ownership

+ - Set input mode deliberately when opening/closing UI contexts.

+ - Set keyboard/user focus to intended root widget.

+ - Ensure focus return path back to gameplay on close.

+ ## 5) Tooltip/Popup Viewport Clamp

+ - Compute desired tooltip position from anchor and cursor/widget geometry.

+ - Clamp final placement to viewport bounds to avoid off-screen rendering.

+ - Debounce high-frequency hover updates to avoid flicker.

+ ## 6) Remove and Cleanup

+ - Remove widget from parent or viewport on close.

+ - Clear timers/delegates and transient references.

+ - Confirm no duplicate instances persist after reopen.

# Constraints

- Keep UI rendering and gameplay state mutation separated.

- Avoid direct gameplay writes from passive display widgets.

- Clamp tooltip and popup placement to viewport bounds.

- Prefer deterministic input ownership and focus transitions.

+ - Keep Slate-only code isolated behind clear bridge boundaries.

+ - Do not rely on per-frame polling if event-driven updates are available.

# Failure Handling

- - If widget does not refresh, verify binding lifecycle and event subscription timing.

- - If input is swallowed, inspect focus path and input mode conflicts.

- - If tooltip flickers, debounce hover source and clamp updates per frame.

+ - Symptom: widget appears but never refreshes.

+ - Locate: construct timing, binding registration, source event firing.

+ - Fix: bind after source readiness and verify event subscription path.

+ - Symptom: widget refreshes once then stops.

+ - Locate: lost delegate handle or widget recreated without rebind.

+ - Fix: rebind on construct and unbind on destruct; prevent duplicate create/destroy churn.

+ - Symptom: input is swallowed by UI unexpectedly.

+ - Locate: current input mode and focused widget path.

+ - Fix: enforce intended input mode and set explicit focus target.

+ - Symptom: keyboard/controller navigation breaks after popup open.

+ - Locate: focus transfer and return path.

+ - Fix: store previous focus owner and restore on popup close.

+ - Symptom: tooltip flickers near screen edges.

+ - Locate: oscillating clamp output and hover source jitter.

+ - Fix: debounce hover updates and clamp with stable viewport metrics.

+ - Symptom: memory growth after repeated open/close.

+ - Locate: stale delegate/timer/reference retention.

+ - Fix: clear bindings and transient refs in teardown.

+ # UE5.6 / UE5.7 Compatibility Notes

+ - UMG lifecycle, input mode, and Slate focus APIs listed above are stable in UE5.6/UE5.7.

+ - Prefer Enhanced Input + explicit UI input mode ownership in both versions.

# Escalation

- Escalate when behavior requires engine-level Slate customization beyond project scope.

- Escalate when UI architecture conflicts with existing CommonUI framework decisions.