I have 2 comboboxes like on the image and would like to know if it is possible to set some kind of text field for the combobox (so the first box would state Members). This w
The effect you are looking for is called a 'watermark', this can be achieved with a value converter as described in the following questions:
Watermark / hint text / placeholder TextBox in WPF
How to display default text "--Select Team --" in combo box on pageload in WPF?
Or via a behaviour, as described in the blogpost:
http://pwlodek.blogspot.com/2009/11/watermark-effect-for-wpfs-textbox.html