add empty boxshadow resource
MODIFY
WalletWasabi.Fluent/Controls/Dialog.axaml
WalletWasabi.Fluent/Controls/Dialog.axaml
<!-- Dialog Fullscreen State -->
<Style Selector="c|Dialog[FullScreenEnabled=True] /template/ Border#PART_Border">
<Setter Property="Margin" Value="0 30 0 0" />
- <Setter Property="BoxShadow" Value="0 0 0 0 #000000" />
+ <Setter Property="BoxShadow" Value="{StaticResource EmptyBoxShadow}" />
</Style>
<Style Selector="c|Dialog[FullScreenEnabled=True] /template/ Panel#PART_DialogHost">
<Setter Property="Margin" Value="0" />

MODIFY
WalletWasabi.Fluent/Styles/Themes/Base.axaml
WalletWasabi.Fluent/Styles/Themes/Base.axaml
<StaticResource x:Key="NotificationCardInformationBackgroundBrush" ResourceKey="SystemAccentColor" />
+ <BoxShadows x:Key="EmptyBoxShadow">0 0 0 0 #000000</BoxShadows>
+
<LinearGradientBrush x:Key="LogoWashoutOpacityMaskGradient" StartPoint="0%,100%" EndPoint="100%,00%">
<LinearGradientBrush.GradientStops>
<GradientStop Color="#4AFFFFFF" Offset="0.1" />

add empty boxshadow resource