Calendars are displayed correctly after "switching" singleDatePicker on/off when datepicker is already initialized.

Here is the situation:

I have two option sets - **A** and **B**. 
**A** has option `singleDatePicker: true`, 
**B** - `singleDatePicker: false`.

At first, datepicker is initialized with options **B** and everything is as expected - can select range, there are two calendars, etc.
Switching to **A** *converts* datepicker to single picker as expected - one calendar.
Switching back to **B**, picker is *converted* to range selector as expected but only with one calendar.

Looks like `.left` calendar is hidden after switching to single mode and never shown again (when switching back to range mode)
Also, when picker is shown on right, calendars are swapped and `.single` is messed up as well as wrong calendar is hidden/shown.