Page_Main.xaml

<Page x:Class="WpfApplication1.Page_Main"
      xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
      xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
      xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" 
      xmlns:d="http://schemas.microsoft.com/expression/blend/2008" 
      xmlns:local="clr-namespace:WpfApplication1"
      mc:Ignorable="d" 
      d:DesignHeight="450" d:DesignWidth="800"         Background="#b0b0b0"
      Title="Page_Main">

    <Grid>
        <Grid.ColumnDefinitions>
            <ColumnDefinition Width="60"/>
            <ColumnDefinition Width="250"/>
            <ColumnDefinition />
        </Grid.ColumnDefinitions>
        <StackPanel x:Name="stackpanel_toolbox" Orientation="Vertical" Background="#FF1F1F1F">

        </StackPanel>
        <StackPanel x:Name="stackpanel_dynarea" Orientation="Vertical" Grid.Column="1">

        </StackPanel>

        <Grid x:Name="grid_graph" Grid.Column="2"/>
    </Grid>
</Page>