It is possible yet to set the value of those Pickers to NULL, but you have to add an additional button yourself that sets a property to NULL. would it be possible to include this functionality in the control itself: some other editfields show a cross, when pressed the content is cleared. also in the flyout, adding as single additional button would be useful. using the DEL keystroke for keyboard access is then also required.
Provide API for focusing custom cell content.