maybe I belong to the minority of users who prefer using the tabulator key instead of the mouse.
Now, if I jump to date field (using tabs) it's necessary to use the mouse unless you want to type the whole date. So whe I take the mouse to move to the newly opened date window, this window very often closes before I could reach it. Seems that the application recognizes that the mouse-cursor is out of the window and thus closes it.
Also when moving out of the window accidentialy the window immediately closes.
Couldn't you make some extra time (1-2 seconds) and/or extra border to avoid this.
Additionally, it would be fine if you could provide some shortcuts in the date field. e.g. entering 15 would select the next upcoming 15th, or even entering "sun" selects the next upcoming sunday... this would help a lot.