DropDownButton or ComboBox with Datagrid as itemtemplate

[TripleNico]

On different places i use the DropDownButton to hide lots of information when it is not needed. When a user whant's to adjust a large collection they can click on it and do there thing. Now i whant something differend. The DropDownButton or ComboBox use a Stackpanel in there Popup to display the ItemSource Items. I want to replace this by using a full Grid, meaning heaving the headers AND rowitems. This because i use the MahApps Datagrid style which is exactly to my need.

For inspiration: http://www.nullskull.com/a/1359/wpf-datagrid-as-combobox-dropdown.aspx https://stackoverflow.com/questions/36615863/combobox-with-datagrid-popup https://stackoverflow.com/questions/8744710/how-to-create-a-combobox-with-a-datagrid-dropdown-in-wpf