use normal css style class name for selectableTextBlock.
MODIFY
WalletWasabi.Fluent/Styles/TextBox.axaml
WalletWasabi.Fluent/Styles/TextBox.axaml
<Setter Property="IsVisible" Value="True" />
</Style>
- <Style Selector="TextBox.selectable_text_block">
+ <Style Selector="TextBox.selectableTextBlock">
<Setter Property="IsReadOnly" Value="True" />
<Setter Property="Margin" Value="0" />
<Setter Property="Padding" Value="0" />
+ <Setter Property="Background" Value="Transparent" />
+ <Setter Property="BorderThickness" Value="0" />
+ <Setter Property="MinHeight" Value="0" />
+ <Setter Property="MinWidth" Value="0" />
<Setter Property="ContextMenu">
<ContextMenu>
<MenuItem Header="Copy" Command="{Binding $parent[TextBox].Copy}" IsEnabled="{Binding $parent[TextBox].CanCopy}" InputGesture="{x:Static TextBox.CopyGesture}"/>

MODIFY
WalletWasabi.Fluent/Views/Dialogs/AboutAdvancedInfoView.axaml
WalletWasabi.Fluent/Views/Dialogs/AboutAdvancedInfoView.axaml
<StackPanel HorizontalAlignment="Center" Spacing="20" MinWidth="380" Margin="30 0 0 0">
<StackPanel>
<TextBlock Classes="Header" Text="Compatible Coordinator Versions" />
- <TextBox Classes="Content selectable_text_block" Text="{Binding BackendCompatibleVersions}" />
+ <TextBox Classes="Content selectableTextBlock" Text="{Binding BackendCompatibleVersions}" />
</StackPanel>
<StackPanel>
<TextBlock Classes="Header" Text="Current Coordinator Version" />
- <TextBox Classes="Content selectable_text_block" Text="{Binding CurrentBackendMajorVersion}" />
+ <TextBox Classes="Content selectableTextBlock" Text="{Binding CurrentBackendMajorVersion}" />
</StackPanel>
<StackPanel>
<TextBlock Classes="Header" Text="Compatible Bitcoin Core and Bitcoin Knots Versions " />
- <TextBox Classes="Content selectable_text_block"
+ <TextBox Classes="Content selectableTextBlock"
Text="{Binding BitcoinCoreVersion}" />
</StackPanel>
<StackPanel>
<TextBlock Classes="Header" Text="Compatible Hardware Wallet Interface Version " />
- <TextBox Classes="Content selectable_text_block"
+ <TextBox Classes="Content selectableTextBlock"
Text="{Binding HwiVersion}" />
</StackPanel>
</StackPanel>

MODIFY
WalletWasabi.Fluent/Views/HelpAndSupport/AboutView.axaml
WalletWasabi.Fluent/Views/HelpAndSupport/AboutView.axaml
<controls:ContentArea.Caption>
<StackPanel Orientation="Horizontal">
<TextBlock Classes="Header" Text="Current Version: " />
- <TextBox Classes="Content selectable_text_block"
+ <TextBox Classes="Content selectableTextBlock"
Text="{Binding ClientVersion}" />
</StackPanel>
</controls:ContentArea.Caption>

use normal css style class name for selectableTextBlock.