ToolBar overflow button isn't visible

In some layouts it is visible, in some it is not. I can not understand why, so here is the minimum reproducible example:

<ui:UiWindow
x:Class="Wpf.Ui.Demo.Views.Windows.TaskManagerWindow"
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:ui="http://schemas.lepo.co/wpfui/2022/xaml"
Title="WPF UI - MS Store Window"
Width="800"
Height="400"
Background="{DynamicResource ApplicationBackgroundBrush}"
WindowCornerPreference="Round"
WindowStartupLocation="CenterScreen"
mc:Ignorable="d">

<Grid>
    <Grid.ColumnDefinitions>
        <ColumnDefinition Width="Auto" />
        <ColumnDefinition Width="*" />
    </Grid.ColumnDefinitions>

    <ToolBarTray>
        <ToolBar>
            <Button Content="Button1"/>
            <Button Content="Button2"/>
            <Button Content="Button3" ToolBar.OverflowMode="Always" />
            <Button Content="Button4" ToolBar.OverflowMode="Always" />
        </ToolBar>
    </ToolBarTray>

    <StackPanel
        Grid.Column="1"/>

</Grid>

</ui:UiWindow>

Also you can remove Grid and leave ToolBarTray itself. Overflow button will appear once you resize window.

Window 11 22000.739
net6.0
wpfui 2.0.1