when a drag event is begins in an empty region of a calendar column, and ends in another calendar column, the shim (opaque blueish layer) must move to the new calendar column, keeping the vertical dimension from the original calendar column
introduced an additional div element in each calendar column in order to create a 15px right margin to be used for adding new events on the same time interval.
- minor issue fixed in getDaySize() and getDayAt() methods, which was occuring after introducing the additional div element in each calendar column for 15px margin. Because of this issue the start and end date in the Add Event window was different for each calendar column, for same hour displayed in the page.

- minor issue fixed in method onDayClick() - the minimum time interval when adding a new event was half an hour instead of one hour as it is default on other views.
- changed recalcHeaderBox() method to properly set the bottom gray region of the header to be same as in the day and week view;
- code style is compliant with the code standard;
- code style is compliant with the code standard;