如何让其他表格覆盖我的表格

how to make other forms goes over my form

我有一个无边框的表格,当我尝试将其他表格拖到上面时,它们只会在下面而不是在上面为什么会这样?

 WindowStartupLocation="CenterScreen" HorizontalAlignment="Left" VerticalAlignment="Top" MouseDown="Window_MouseDown" Topmost="True" x:Name="win" WindowStyle="None" Height="{x:Static SystemParameters.PrimaryScreenHeight}"  Width="{x:Static SystemParameters.PrimaryScreenWidth}" ResizeMode="CanResizeWithGrip" AllowsTransparency="True" Visibility="Visible" SnapsToDevicePixels="True" IsHitTestVisible="True" Loaded="win_Loaded">
<WindowChrome.WindowChrome>
    <WindowChrome 
    CaptionHeight="0"
    ResizeBorderThickness="5" />
</WindowChrome.WindowChrome>

你设置了Topmost="True"。只需删除它。