The input method input box cannot be correctly positioned to the edge of TextBox with MaterialDesignInXamlToolKit

Question

I have found a bug that affects the user experience. In the dialog opened by DialogHost, if I want to use input method to input content in TextBox, the input method input box cannot be correctly positioned to the edge of TextBox, but appears in the upper left corner of the screen. Does anyone know how to solve this problem? This is my Xaml code:

<Window x:Class="DelayPenaltySystem.MainWindow"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    xmlns:local="clr-namespace:DelayPenaltySystem"
    mc:Ignorable="d"
    xmlns:md="http://materialdesigninxaml.net/winfx/xaml/themes"
    TextElement.Foreground="{DynamicResource MaterialDesignBody}"
    Background="{DynamicResource MaterialDesignPaper}"
    TextElement.FontWeight="Normal"
    TextElement.FontSize="14"
    FontFamily="{md:MaterialDesignFont}"
    Icon="logo.png"
    Height="800"
    Width="1200"
    WindowStartupLocation="CenterScreen"
    WindowStyle="None"
    ResizeMode="NoResize"
    BorderThickness="0"
    Loaded="Window_Loaded">
<md:DialogHost Identifier="RootDialog"
               DialogTheme="Inherit">
    <Grid>
        ...
    </Grid>
</md:DialogHost>

This is the picture