# Peek Window

RadOfficeNavigationBar provides popup preview option for its elements when the mouse is over a them. This functionality is disabled by default. To enable it, you can set the **EnablePeekPopup** property to true.

![WinForms RadOfficeNavigationBar Peek Window](https://www.telerik.com/products/winforms/documentation/assets/cac5a76c0a3ed71f9f49066537ba4810/officenavigationbar-peek-window001.png)

```C#
this.radOfficeNavigationBar1.EnablePeekPopup = true;
```

```VB.NET
Me.radOfficeNavigationBar1.EnablePeekPopup = True
```

To set a content for each peek window, we can use the **PeekPopupOpening** event. In the event handler, we have access to the current hovered RadPageViewItem and depending on it, we can set the **Page.PeekPopupContent** property. This property is of type **Control**.

> The Peek Window will take the size of its content. This needs to be considered while using UserControl as a content of the Peek Window.

```C#
private void OfficeNavigationBarElement_PeekPopupOpening(object sender, Telerik.WinControls.UI.OfficeNavigationBar.RadPageViewPeekPopupEventArgs e)
{
    RadLabel content = new RadLabel();
    content.Text = e.Item.Text;
    content.Font = new Font("Segoe UI Semibold", 27f);
    content.LoadElementTree();
    e.PeekPopupContent = content;
}
```

```VB.NET
Private Sub OfficeNavigationBarElement_PeekPopupOpening(ByVal sender As Object, ByVal e As Telerik.WinControls.UI.OfficeNavigationBar.RadPageViewPeekPopupEventArgs)
    Dim content As RadLabel = New RadLabel()
    content.Text = e.Item.Text
    content.Font = New Font("Segoe UI Semibold", 27.0F)
    content.LoadElementTree()
    e.PeekPopupContent = content
End Sub
```

In the following image we can see the Peek Window content when it hosts a custom user control.

![WinForms RadOfficeNavigationBar Custom Peek Window](https://www.telerik.com/products/winforms/documentation/assets/4a33f9adc3fa5db74f18a623574a9e86/officenavigationbar-peek-window002.png)

## See Also

* [Getting Started](https://www.telerik.com/products/winforms/documentation/controls/officenavigationbar/getting-started)

* [Design Time](https://www.telerik.com/products/winforms/documentation/controls/officenavigationbar/design-time)

* [Structure](https://www.telerik.com/products/winforms/documentation/controls/officenavigationbar/structure)