I'm working on a specialized word processor. I'm just wondering if someone can help me with my basic layout. I'm having a bit of trouble figuring out how to adjust my center panel in a dock panel. I can't seem to get it to a good page width. I've tried margin attribute but that does margin around the whole control, and width attribute has a weird affect. I have to set it to 600 to get it about right, but in the the solution view is stretches out off the right side of the form. Looks okay on play, but would like to no how to make it properly...

<Window x:Class="MainWindow"
    Title="Water SV1" Height="350" Width="525" WindowState="Maximized">
    <DockPanel LastChildFill="True">
        <Menu DockPanel.Dock="Top">
            <MenuItem Header="Example"></MenuItem>
            <MenuItem Header="Example"></MenuItem>
            <MenuItem Header="Example"></MenuItem>
            <MenuItem Header="Example"></MenuItem>
        <ToolBar DockPanel.Dock="Top"></ToolBar>
        <StatusBar DockPanel.Dock="Bottom" Height="20">
            <TextBlock Name="StatusBar"></TextBlock>
        <StackPanel DockPanel.Dock="Left" Width="180" Background="{DynamicResource {x:Static SystemColors.ActiveBorderBrushKey}}"></StackPanel>
        <StackPanel DockPanel.Dock="Right" Width="180" Background="{DynamicResource {x:Static SystemColors.ActiveBorderBrushKey}}"></StackPanel>
        <RichTextBox Name="WordProcessor"></RichTextBox>
Thanks for any help