command on click behavior
ADD
WalletWasabi.Fluent/Behaviors/ExecuteCommandOnClickBehavior.cs
+using System.Windows.Input;
+using Avalonia;
+using Avalonia.Controls;
+using Avalonia.Input;
+
+namespace WalletWasabi.Fluent.Behaviors
+{
+ public class ExecuteCommandOnClickBehavior : AttachedToVisualTreeBehavior<Control>
+ {
+ public static readonly StyledProperty<ICommand?> CommandProperty =
+ AvaloniaProperty.Register<ExecuteCommandOnClickBehavior, ICommand?>(nameof(Command));
+
+ public ICommand? Command
+ {
+ get => GetValue(CommandProperty);
+ set => SetValue(CommandProperty, value);
+ }
+
+ protected override void OnAttachedToVisualTree()
+ {
+ AssociatedObject.PointerReleased += OnPointerReleased;
+ }
+
+ protected override void OnDetaching()
+ {
+ base.OnDetaching();
+
+ AssociatedObject.PointerReleased -= OnPointerReleased;
+ }
+
+ private void OnPointerReleased(object? sender, PointerReleasedEventArgs e)
+ {
+ Command?.Execute(default);
+ }
+ }
+}

MODIFY
WalletWasabi.Fluent/Views/Wallets/Send/SendView.axaml
WalletWasabi.Fluent/Views/Wallets/Send/SendView.axaml
Watermark="(e.g. Bitcoin address or PayJoin URL)">
<i:Interaction.Behaviors>
<behaviors:FocusOnAttachedBehavior />
+ <behaviors:ExecuteCommandOnClickBehavior Command="{Binding PasteCommand}" />
</i:Interaction.Behaviors>
<TextBox.InnerRightContent>
<StackPanel Orientation="Horizontal" VerticalAlignment="Center" Spacing="10" Margin="10 0">

command on click behavior