I had the following XAML looking just as I want it to look. It's basically a dropdown menu with checkboxes and some text to them.
So with most of the controls that offer up things from ItemSource there's a nifty built in feature that allows you to specify how each item should look/behave etc. So you can specify each Item in your ComboBox's by setting your own ItemTemplate.
Since a ComboBox just uses an ItemsControl to list its items, you can utilize this via ComboBox.ItemTemplate to make your items however you like, in this case probably something like (in pseudo).
<ComboBox> <ComboBox.ItemTemplate> <DataTemplate> <CheckBox> </DataTemplate> </ComboBox.ItemTemplate> </ComboBox>
Hope this helps, its some pretty handy info to know for when you want to start customizing Item generated lists between wpf, silverlight, wp, win-rt, etc. Cheers!