WPF Nested Popup does not close - wpf

Question

I have a window with an Image that shows a Popup from its MouseEnter event handler:
private void theImage_MouseEnter(object sender, MouseEventArgs e)
{
contolPopup.IsOpen = true;
}
There is a button in this contolPopup that shows another Popup from its Click event handler:
private void setButton_Click(object sender, RoutedEventArgs e)
{
paramPopup.IsOpen = true;
}
This paramPopup behaves a bit strange just after it is shown: it does not close if I click somewhere outside it, but if I click on some control inside this paramPopup and then click somewhere outside, it closes fine.
What can cause this behavior?
I tried to focus paramPopup, but this does not help:
private void setButton_Click(object sender, RoutedEventArgs e)
{
paramPopup.IsOpen = setButton.IsChecked??false;
paramPopup.Focus();
}
Popup.StaysOpen is set to false for both Popups. I use .NET 4.0
Below I provided full source code:
fist popup is opened from a window:
<Window x:Class="GeoControls.WebcamWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="clr-namespace:GeoControls"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
SizeChanged="Window_SizeChanged" Loaded="Window_Loaded" SizeToContent="WidthAndHeight" ResizeMode="NoResize"
Title="{Binding Name}"
MouseEnter="theImage_MouseEnter" MouseLeave="theImage_MouseLeave" MouseLeftButtonUp="Window_MouseLeftButtonUp" Closed="Window_Closed">
<Grid Background="Black">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="*"/>
<ColumnDefinition Width="Auto"/>
</Grid.ColumnDefinitions>
<Image Grid.Row="0" Grid.ColumnSpan="2" Name="theImage" Width="{Binding CurrentResolution.Width}" Height="{Binding CurrentResolution.Height}" />
<TextBlock Name="waitingTextBlock" Grid.Row="0" Text="Waiting the response from TV Server..." Foreground="White" VerticalAlignment="Center" HorizontalAlignment="Center"/>
<Popup Name="contolPopup" StaysOpen="False" PlacementTarget="{Binding ElementName=theImage}" PopupAnimation="Scroll" Placement="Left" AllowsTransparency="True">
<Border CornerRadius="10" BorderThickness="1" BorderBrush="Black" Padding="10" Background="White">
<local:WebcamControl x:Name="webcamControl" Background="White">
</local:WebcamControl>
</Border>
</Popup>
</Grid>
</Window>
the second popup is opened by ParamButtons contained in WebcamControl contained in the first popup:
<UserControl x:Class="GeoControls.ParamButtons"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
mc:Ignorable="d"
xmlns:local="clr-namespace:GeoControls"
d:DesignHeight="30" d:DesignWidth="300">
<Grid>
............ omitted some code here................
<Popup Name="paramPopup" StaysOpen="False" PlacementTarget="{Binding ElementName=setButton}" AllowsTransparency="True" Closed="paramPopup_Closed">
<Border Focusable="True" CornerRadius="10" BorderThickness="1" BorderBrush="Black" Padding="10" Background="White">
<Grid>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="300"/>
<ColumnDefinition Width="50"/>
<ColumnDefinition Width="50"/>
</Grid.ColumnDefinitions>
<local:ParamSlider Grid.Column="0" x:Name="paramSlider" />
<Button Content="OK" Click="okButton_Click" Grid.Column="1" Margin="5" />
<Button Content="Cancel" Click="cancelButton_Click" Grid.Column="2" Margin="5" />
</Grid>
</Border>
</Popup>
</Grid>
</UserControl>