Patterns and troubleshooting

HUD from replicated health

1. Server owns and mutates health.
2. Health replicates with RepNotify or GAS attribute delegates.
3. Local presenter subscribes for the owning player.
4. Presenter emits normalized value and formatted text.
5. HUD updates progress/text once per change.

Route GAS-owned health to $unreal-gas-attributes-effects and replication to $unreal-replication.

Pause/inventory screen

1. Push an activatable screen onto the game-menu stack.
2. Apply the screen input config and UI Mapping Context.
3. Populate data before selecting desired focus.
4. Back deactivates the top screen.
5. Deactivation removes context/subscriptions and restores prior focus.

Remember that a local pause does not automatically pause an authoritative multiplayer server.

Inventory list

• Store inventory entries as item data/UObjects, not entry widgets.
• Use ListView or TileView virtualization.
• In entry initialization/assignment, overwrite every visual field and selection state.
• Preserve selection by stable item identity across refresh.
• Submit move/equip/drop intent to authoritative gameplay; wait for replicated confirmation.

Modal confirmation

• Push to the modal layer above menus.
• Give it an explicit default focus and cancel/Back route.
• Disable duplicate submission after accept.
• Return a semantic result callback; do not let the modal mutate distant gameplay state directly.

Diagnostic table

Symptom	Likely cause	First check
UI only works for host	wrong local-player ownership or client lacks presentation hookup	remote client + owning player
Event fires repeatedly after reopen	duplicate Construct/activation binding	symmetric unbind and guard
Controller cannot enter screen	no focusable desired target	activation focus path
Back leaks to gameplay	inactive/mis-layered screen or duplicate actions	action router and contexts
List rows show stale data	pooled entry not fully reset	item-assignment handler
Screen hitches on first open	synchronous construction/asset load	trace load and split/preload
Static screen costs every frame	Tick/raw bindings/invalidations	Slate Insights and compiler rules
UI claims action succeeded early	local widget mutated canonical state	authoritative confirmation path

Shipping gate

• All screens operable with every supported input device.
• Deterministic focus and Back behavior at every layer.
• Split-screen/local-player isolation verified if supported.
• Resolution, DPI, safe-zone, localization, and maximum-text-scale matrix passes.
• Remote-client state matches authoritative gameplay under latency and packet loss.
• UI trace meets target budget with no growing widget/delegate count.