- ViewModels inherit `BaseViewModel` and expose properties via `SetProperty(ref _field, value)` so that `CommandManager.InvalidateRequerySuggested` is automatically called on change.
- User actions are bound to `ICommand` properties implemented as lazy-initialized `RelayCommand`/`RelayCommandAsync` fields, with optional `canExecute` predicates passed at construction.
- ClassicUO command-line flags are declared declaratively on `ClassicOptions` properties using `[ClassicOption(...)]` attributes rather than hard-coded string literals, and consumed uniformly via reflection in `ReadClassicOptions`/`BuildClassicOptions`.
- Per-user configuration is serialized/deserialized manually against `Newtonsoft.Json.Linq.JObject`/`JArray` instead of using POCO serialization, with explicit field-by-field read/write paths in `MainViewModel.Closing` and the constructor.
- Singleton services (e.g. `ShardManager`) use double-checked locking with a static `_lock` object exposed through a `GetInstance()` factory method.