This issue was discussed on:
http://stackoverflow.com/questions/9703822/fullcalendar-draggable-object-rejects-fullcalendar-as-droppable-even-though-ful
Repeating below:
I have set up FullCalendar to accept drops, which it does. But the draggable object, which I have constructed with revert:'invalid' does not seem to recognize the dates on FullCalendar as droppable, and reverts back.
A demonstration of this is at: http://jsfiddle.net/flavius/DEsdN/5/
A workaround can be seen at: http://jsfiddle.net/flavius/CZQkm/4/
The workaround is to execute the following command after fullcalendar has been instantiated:
$('#calendar .fc-content table .fc-widget-content > div').droppable();
which makes all of the calendar date HTML elements droppable. The above, however, depends on the droppable component being installed....but it is not included in the jquery-ui-1.8.17.custom.min.js provided with fullcalendar.
In any case, it would also seem to me that if I set "droppable: true" when instantiating fullcalendar, then I should not have to instrument the individual calendar dates as droppable myself.
Mergedinto: 550