How to keep pop up open until it has focus in wpf

How to keep pop up open until it has focus in wpf

I am having following XAML for showing a popup on mouse enter event of a
text box and close the popup on the mouse leave event of textbox. So, when
I try to go to popup then mouse leave event is called and popup is closed.
So what I want popup should not be closed if I am having focus on the
popup rather popup should be closed if I have clicked on the popup or
mouse is not over pop up.
Note: But popup should be closed on mouse leave if I am not having focus
on popup.
<Window x:Class="WpfApplication4.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Title="MainWindow" Height="350" Width="525">
<Grid>
<Control VerticalAlignment="Top">
<Control.Template>
<ControlTemplate>
<StackPanel>
<TextBox x:Name="MyText"></TextBox>
<Popup x:Name="Popup" PopupAnimation="Fade"
VerticalAlignment="Top">
<Border Background="Red">
<TextBlock>Test Popup Content</TextBlock>
</Border>
</Popup>
</StackPanel>
<ControlTemplate.Triggers>
<EventTrigger RoutedEvent="UIElement.MouseEnter"
SourceName="MyText">
<BeginStoryboard>
<Storyboard>
<BooleanAnimationUsingKeyFrames
Storyboard.TargetName="Popup"
Storyboard.TargetProperty="(Popup.IsOpen)">
<DiscreteBooleanKeyFrame
KeyTime="00:00:00" Value="True"/>
</BooleanAnimationUsingKeyFrames>
</Storyboard>
</BeginStoryboard>
</EventTrigger>
<EventTrigger RoutedEvent="UIElement.MouseLeave"
SourceName="MyText">
<BeginStoryboard>
<Storyboard>
<BooleanAnimationUsingKeyFrames
Storyboard.TargetName="Popup"
Storyboard.TargetProperty="(Popup.IsOpen)">
<DiscreteBooleanKeyFrame
KeyTime="00:00:00" Value="False"/>
</BooleanAnimationUsingKeyFrames>
</Storyboard>
</BeginStoryboard>
</EventTrigger>
</ControlTemplate.Triggers>
</ControlTemplate>
</Control.Template>
</Control>
</Grid>
</Window>