calendar-bundle/src/Resources/contao/dca/tl_calendar_events.php
public function loadEndTime($value, Contao\DataContainer $dc)
	{
		$return = strtotime('1970-01-01 ' . date('H:i:s', $value));

		// Return an empty string if the start time is the same as the end time (see #23)
		if ($dc->activeRecord && $return == $dc->activeRecord->startTime)
		{
			return '';
		}

		// Return an empty string if no time has been set yet
		if ($dc->activeRecord && $return - $dc->activeRecord->startTime == 86399)
		{
			return '';
		}

		return strtotime('1970-01-01 ' . date('H:i:s', $value));
	}
public function loadEndTime($value, Contao\DataContainer $dc)
	{
		$return = strtotime('1970-01-01 ' . date('H:i:s', $value));

		// Return an empty string if the start time is the same as the end time (see #23)
		if ($dc->activeRecord && $return == $dc->activeRecord->startTime)
		{
			return '';
		}

		// Return an empty string if no time has been set yet
		if ($dc->activeRecord && $return - $dc->activeRecord->startTime == 86399)
		{
			return '';
		}

		return strtotime('1970-01-01 ' . date('H:i:s', $value));
	}
Set the end time to an empty string (see #23)

@param integer              $value
@param Contao\DataContainer $dc

@return integer