It'll be too late for my project, but i guess this could be helpful to other people...

There is a feature in the "default" .net Text Edit control, that one can find on "Other". That feature is "AutoCompleteSource", which among other things allow developper to set an -- you guessed it -- auto completion source such as "file system directories" or "Recently Used list". Given end user would type "C:\Doc", the ButtonEdit would autofill the remaining "uments and settings".

In my project i had to fall back to the default control and the addition to two classic SimpleButtons, which is ugly indeed.

Anyway, the suite is absolutely great!