Change design size
MODIFY
WalletWasabi.Fluent/Views/ResponsivePanelDemo/ResponsiveLayoutDemoView.axaml
WalletWasabi.Fluent/Views/ResponsivePanelDemo/ResponsiveLayoutDemoView.axaml
xmlns:c="clr-namespace:WalletWasabi.Fluent.Controls"
xmlns:conv="using:WalletWasabi.Fluent.Converters"
xmlns:vm="using:WalletWasabi.Fluent.ViewModels.ResponsivePanelDemo"
- mc:Ignorable="d" d:DesignWidth="1300" d:DesignHeight="850"
+ mc:Ignorable="d" d:DesignWidth="1250" d:DesignHeight="700"
x:Class="WalletWasabi.Fluent.Views.ResponsivePanelDemo.ResponsiveLayoutDemoView">
<UserControl.DataContext>
<vm:ResponsiveLayoutDemoViewModel/>

MODIFY
WalletWasabi.Fluent/Views/ResponsivePanelDemo/ResponsivePanelDemoView.axaml
WalletWasabi.Fluent/Views/ResponsivePanelDemo/ResponsivePanelDemoView.axaml
xmlns:c="clr-namespace:WalletWasabi.Fluent.Controls"
xmlns:conv="using:WalletWasabi.Fluent.Converters"
xmlns:vm="using:WalletWasabi.Fluent.ViewModels.ResponsivePanelDemo"
- mc:Ignorable="d" d:DesignWidth="1000" d:DesignHeight="850"
+ mc:Ignorable="d" d:DesignWidth="1250" d:DesignHeight="700"
x:Class="WalletWasabi.Fluent.Views.ResponsivePanelDemo.ResponsivePanelDemoView">
<UserControl.DataContext>
<vm:ResponsivePanelDemoViewModel/>

Change design size