Use StringConverters.IsNotNullOrEmpty
MODIFY
WalletWasabi.Gui/Controls/WalletExplorer/SendControlView.xaml
WalletWasabi.Gui/Controls/WalletExplorer/SendControlView.xaml
<converters:BooleanStringConverter x:Key="BooleanStringConverter" />
<converters:FeeTargetTimeConverter x:Key="FeeTargetTimeConverter" />
<converters:UsdExchangeRateAmountToolTipConverter x:Key="UsdExchangeRateAmountToolTipConverter" />
- <converters:IsNotNullOrEmptyBoolConverter x:Key="IsNotNullOrEmptyBoolConverter" />
</UserControl.Resources>
<i:Interaction.Behaviors>
<behaviors:ClearPropertyOnLostFocusBehavior TargetProperty="{Binding SelectedCoin}" />
</i:Interaction.Behaviors>
</controls:ExtendedTextBox>
- <controls:ExtendedTextBox IsVisible="{Binding PayjoinEndPoint, Converter={StaticResource IsNotNullOrEmptyBoolConverter}}" Classes="monospaceFont" Text="{Binding PayjoinEndPoint}" Watermark="PayJoin EndPoint" UseFloatingWatermark="True" />
+ <controls:ExtendedTextBox IsVisible="{Binding PayjoinEndPoint, Converter={x:Static StringConverters.IsNotNullOrEmpty}}" Classes="monospaceFont" Text="{Binding PayjoinEndPoint}" Watermark="PayJoin EndPoint" UseFloatingWatermark="True" />
<suggestions:SuggestLabelView DataContext="{Binding LabelSuggestion}" />

DELETE
WalletWasabi.Gui/Converters/IsNotNullOrEmptyBoolConverter.cs
-using Avalonia.Data.Converters;
-using System;
-using System.Globalization;
-
-namespace WalletWasabi.Gui.Converters
-{
- internal class IsNotNullOrEmptyBoolConverter : IValueConverter
- {
- public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
- {
- if (value is null)
- {
- return false;
- }
-
- if (!string.IsNullOrEmpty(value.ToString()))
- {
- return true;
- }
-
- return false;
- }
-
- public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
- {
- throw new NotImplementedException();
- }
- }
-}

Use StringConverters.IsNotNullOrEmpty