I am attempting to create rounded corners on my DataGrid from the March 2009 WPFToolkit. To begin with I have applied a control template containing a border w/ a rounded corner to the DataGridColumnHeader items in the first (upper left corner) and
last (upper right corner) columns. This works ok, but it reveals the white background of the underlying container for the column headers (which is not what i want). Instead I would like the background color of the main application to show through.
Upon inspection of the visual tree with snoop, it appears that the containing element for the column headers is a DataGridColumnHeadersPresenter. Setting the background to transparent on this element has no effect. Any ideas?