You can restrict the portion of a window's client area you want to display in the thumbnail preview by setting the ClipControl property to the ID of one of the form's elements.

In the Designer

1. Click the smart tag to open the C1TaskbarButton Tasks list.
2. Click the Clip Control drop-down arrow and select one of the elements on your page from the list. For example, if you had a generic Button ("button1") control on your form and wanted to clip the thumbnail image to that button, you'd select button1.

In Code

To restrict the thumbnail image to one element of your form, set the ClipControl property to the ID of that element. For example:

To write code in Visual Basic

C1TaskbarButton1.Thumbnail.ClipControl = button1

To write code in C#

c1TaskbarButton1.Thumbnail.ClipControl = button1;