Tab Key Issue when input Mode = TimePicker

[Ed]

I'm seeing the following behavior with the DateTimePicker when InputMode=TimePicker.

1. With cursor in textbox, hit down arrow to open time picker popup.
2. Then hit tab key to move focus to list of selectable times
3. Keep hitting tab until focus is on the time you would like to select
4. Hit enter.  Popup closes but time was NOT selected.  Appears that only a mouse click will select a time.  Is there a setting that will enable selecting a time with the keyboard?

Also,

1. With cursor in textbox, hit down arrow to open time picker popup.
2. Then hit tab key to move focus to list of selectable times
3. Keep hitting tab until focus is on the time you would like to select
4. Hit enter and popup closes.
5. Hit down arrow to open time picker.  
6. Hit tab key to move focus to a selectable time.  Focus does not move to list of times.  How can I get the focus back into the popup to select a time with the keyboard?

Thanks in advance!