Keep Orage window as small as possible in the corner

Orage's window remembers its size and position and the window gets longer when ToDos and Events are added and displayed under the calendar. When ToDos and Events end or get removed, the window keeps the same size as if they were still present as it remembers its last size. A user wanting Orage to be as small as possible as to manually resize it to minimum size or keep a large blank area under the calendar. It would be nice if the window got shorter as items were removed.

Correspondingly, if the window is snapped to the bottom of the screen (or to the XFCE panel when it's horizontal and at the bottom), as it shrinks to its minimum size, it should remain snapped to the bottom. Otherwise, as the blank area under the calendar is removed, Orage would now be floating a few lines above the panel/bottom.