New Post: Toolkit Controls in a Toolbar

You're right, in your case they look the same (probably because the controls are inside a StackPanel? or because the ToolBar is not inside a ToolBarTray?).

Usually I create my toolbars like this:

<Window x:Class="StyleTest.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:xctk="http://schemas.xceed.com/wpf/xaml/toolkit"
        Title="MainWindow" Height="100" Width="500">
    <DockPanel>
        <ToolBarTray DockPanel.Dock="Top">
            <ToolBar ToolBarTray.IsLocked="True" >
                <TextBox Width="70" Text="TextBox" />
                <xctk:IntegerUpDown Width="70" Value="100" />
                <Button>Button</Button>
                <xctk:DropDownButton>DropDownButton</xctk:DropDownButton>
            </ToolBar>
        </ToolBarTray>
    </DockPanel>
</Window>

In this case the TextBox and the Button change to a flat appearance (which is what I want) but the Toolkit controls keep their default non-flat style. I'm using Windows 7.