When day-long ranges are allowed, if one tries to select a date range that is of two days duration by drag-and-dropping mouse cursor, it ends up selecting only one day.
For example, if you try to select a date range of "May 13th to May 14th", by pushing mouse button at "May 13th", drag the mouse cursor to "May 14th", and pull the mouse button while the cursor is on "May 14th", I end up only selecting one-day date range "May 13th to May 13th".
If I drag my mouse cursor to outside of "May 13th" and "May 14th", and then finally come back to "May 14th", I can indeed select two days period.
When day-long ranges are allowed, if one tries to select a date range that is of two days duration by drag-and-dropping mouse cursor, it ends up selecting only one day. For example, if you try to select a date range of "May 13th to May 14th", by pushing mouse button at "May 13th", drag the mouse cursor to "May 14th", and pull the mouse button while the cursor is on "May 14th", I end up only selecting one-day date range "May 13th to May 13th". If I drag my mouse cursor to outside of "May 13th" and "May 14th", and then finally come back to "May 14th", I can indeed select two days period.