[TYPO3-calendar] BUG: FE Calendar Selection Field does not show (pre-)selected Calendar

[PM]

In the plugin backend configuration I have:

Filters --> Calendar selection mode: "Show all calendars (don't care ...)"
Filters --> Calendar selection --> Selected Items: EMPTY

But the Dropdown-Field in the classic-template Month-View always 
preselects the last calender.

Reason:

<select name="tx_cal_controller[calendar]" size="1" onchange="submit();">
<option value="">All Combined</option>
<option value="9" selected="selected">Calendar 1</option>
<option value="7" selected="selected">Calendar 2</option>
<option value="1" selected="selected">Calendar 3</option></select>

Solution:

If all calendars are selected don't set all to "selected" but only "All 
Combined".