enable compiled bindings on mainwindow.
MODIFY
WalletWasabi.Fluent/Views/MainWindow.axaml
WalletWasabi.Fluent/Views/MainWindow.axaml
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:behaviors="using:WalletWasabi.Fluent.Behaviors"
xmlns:i="using:Avalonia.Xaml.Interactivity"
+ xmlns:viewModels="clr-namespace:WalletWasabi.Fluent.ViewModels"
mc:Ignorable="d" d:DesignWidth="536" d:DesignHeight="459"
x:Class="WalletWasabi.Fluent.Views.MainWindow"
+ x:DataType="viewModels:MainViewModel"
x:Name="MainWindow"
+ x:CompileBindings="True"
MinWidth="640" MinHeight="480"
Width="{Binding WindowWidth, Mode=TwoWay}"
Height="{Binding WindowHeight, Mode=TwoWay}"

enable compiled bindings on mainwindow.