WPF ComboBox with Custom Popup - Focus on filter Textbox
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We have a ComboBox with Filter working well except for one item - The focus needs to be on the filter textbox when the popup opens.

Using Snoop, I found a DropDownBehavior.FocusOnOpen that works well when nothing is selected, but I don't know how to set the value, and it doesn't work when a value is already selected.

See [http://gregandora.wordpress.com/2012/01/25/filtering-items-in-a-wpf-combobox][1]/ for the basic combobox. I changed alot and moved the template into the template property instead of a style.

The question is: 

 1. How can I set the focus to the combobox on opening the dropdown? I tried using ondropdown open, and it did not work.
 2. How can I set DropDownBehavior.FocusOnOpen to true? I can't find anything on the web about it.


Thanks!

  [1]: http://gregandora.wordpress.com/2012/01/25/filtering-items-in-a-wpf-combobox