Copilot instructions

1---
2applyTo:
3  - "src/Controls/src/Core/Handlers/Items/*.Windows.cs"
4  - "src/Controls/src/Core/Handlers/Items/*.windows.cs"
5---
6# CollectionView — Windows (Items/ Handler)
7 
8Items/ is the **ONLY** Windows CollectionView implementation. Items2/ has NO Windows code.
9 
10## WinUI ListView/ItemsRepeater Patterns
11- Preserve WinUI XAML styles applied via native theming — clearing a MAUI property must restore the style-applied value, not a hardcoded default
12- `double.NaN` is the WinUI convention for unconstrained dimensions — do not confuse with MAUI's `double.PositiveInfinity`
13- Use `DispatcherQueue.TryEnqueue` for deferred UI thread work — do not use `Dispatcher.BeginInvoke`
14 
15## Data Source and Change Notifications
16- Handle all `ObservableCollection` change actions (Add, Remove, Replace, Move, Reset) with range-scoped updates
17- Avoid full source refresh (`NotifyDataSetChanged` equivalent) — it kills selection state and scroll position
18- Selection mode changes must propagate correctly to the native `SelectionMode` property
19 
20## Layout Configuration
21- `ItemsLayout` changes require reconfiguration of the underlying panel (e.g., `ItemsWrapGrid`, `ItemsStackPanel`)
22- Verify that `ItemsLayout.Span` for grid layouts maps correctly to WinUI's `MaximumRowsOrColumns`
23 
24## Cross-Platform Consistency
25- Default values for control properties must produce the same visual result as Android and iOS
26- Event firing order (selection changed, scrolled) should match other platforms for the same user interaction
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