I found several problems with the DateTimePicker:
- UpdateSourceTrigger=PropertyChanged is ignored, it still only updates when leaving focus -- which is problematic when used inside a ToolBar since ToolBars have its own focus scope and so it never looses focus automatically when buttons outside the ToolBar are being clicked
- The DropDown does not work when the DTP is placed inside a ToolBar: You only can click days of the currently showing months but you are not able to change the month or the year
- With enabled YearSelectionEnabled it's somewhat confusing that mouse-wheel-up and the navigation buttons down are scrolling in the same direction
<shared:DateTimePicker FirstDayOfWeek="Monday" IsEditable="True" ClearButtonVisible="True"
TodayButtonVisible="True" WeekNumbersVisible="True" YearSelectionEnabled="True"
TodayButtonContent="heute" ClearButtonContent="leeren"
Value="{Binding DataObj.Start, UpdateSourceTrigger=PropertyChanged}" />