Set 100% Width of a Page in Expression Blend

You can set 100% width of a page (User Control) in Expression Blend by removing width attribute of UserControl. BUT then you won't be able to see the page in design mode.

To overcome this issue, you simply set DesignWidth and DesignHeight of UserControl as following:

<UserControl
 xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
 xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
 x:Class="Mindcracker.Page"
 d:DesignWidth="1100" d:DesignHeight="800"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    mc:Ignorable="d" xmlns:vsm="clr-namespace:System.Windows;assembly=System.Windows">