Hi,

XamComboEditor relies on there being a TextBox in its template therefore the XamComboEditor itself probably can't be modified to make use of something other than a TextBox for edit portion.

 However one option might be to modify the XamMaskedEditor's control template to include a drop-down button that drops down a popup that contains drop-down items. For example, you could have a popup that contains ListBox that displays your items and bind the selected item of the list box to the value of the xam masked editor.

Sandip