Listbox items not wrapping, tried almost everything. it might be due to ItemTemplate - wpf

Question

**Tried adding wrap panel as parent, as child, as item template parent, but didn't work
**
<UserControl.Resources>
<DataTemplate x:Key="CredentialTemplate" DataType="{x:Type local:Credentials}">
<WrapPanel Width="800" Orientation="Horizontal">
<Grid Background="Red" Width="160" Height="160">
<Grid.RowDefinitions>
<RowDefinition Height="40"/>
<RowDefinition/>
<RowDefinition/>
</Grid.RowDefinitions>
<Grid.ColumnDefinitions>
<ColumnDefinition/>
<ColumnDefinition/>
</Grid.ColumnDefinitions>
<TextBlock Grid.Row="0" Grid.Column="0" Text="{Binding FileName}" FontWeight="Bold" Margin="0,0,10,0"/>
<Button Grid.Row="1" Grid.Column="0" x:Name="btnCopyUsername" Tag="{Binding Button}" Content="Copy Username" Click="OnCopyUsernameButtonClicked" Margin="10"/>
<Button Grid.Row="1" Grid.Column="1" x:Name="btnCopyPassword" Tag="{Binding Button}" Content="Copy Password" Click="OnCopyPasswordButtonClicked" Margin="10"/>
<Button Grid.Row="2" Grid.Column="0" x:Name="btnEdit" Tag="{Binding Button}" Content="Edit" Click="OnEditButtonClicked" Margin="10"/>
<Button Grid.Row="2" Grid.Column="1" x:Name="btnCopyBoth" Tag="{Binding Button}" Content="Copy Both" Click="OnCopyBothButtonClicked" Margin="10"/>
</Grid>
</WrapPanel>
</DataTemplate>
</UserControl.Resources>
<WrapPanel Width="900" Background="Yellow">
<ListBox ItemsSource="{Binding Credentials}" ItemTemplate="{StaticResource CredentialTemplate}" ScrollViewer.HorizontalScrollBarVisibility="Disabled" ScrollViewer.VerticalScrollBarVisibility="Disabled">
<ListBox.ItemsPanel>
<ItemsPanelTemplate>
<WrapPanel Orientation="Horizontal" Background="Green" Margin="10"/>
</ItemsPanelTemplate>
</ListBox.ItemsPanel>
</ListBox>
</WrapPanel>
</UserControl>
It might be the grid control that not letting wrap, normally without item template it should work
Screenshot

Answer 1

I explored this issue with a simplified version of your markup.
I don't have a credentials class, but what's in the grids doesn't matter.
My markup has less wrappanels:
<Grid>
<Grid.Resources>
<DataTemplate x:Key="CredentialTemplate">
<Grid Background="Red" Width="40" Height="40">
</Grid>
</DataTemplate>
</Grid.Resources>
<ListBox ItemsSource="{Binding Points}"
ItemTemplate="{StaticResource CredentialTemplate}"
ScrollViewer.HorizontalScrollBarVisibility="Disabled"
ScrollViewer.VerticalScrollBarVisibility="Disabled">
<ListBox.ItemsPanel>
<ItemsPanelTemplate>
<WrapPanel Orientation="Horizontal"
Background="Green" Margin="10"/>
</ItemsPanelTemplate>
</ListBox.ItemsPanel>
</ListBox>
</Grid>
I've got 30 Points in my viewmodel.
My grid is smaller
Wraps ok: