Unable to Add Checkbox to lightbox popup

I get the error:
Cannot read property ‘nextSibling’ of null

Here is my code:

My Json object looks like this:

“start_date”: “2015-2-10 16:51:25”,
“end_date”: “2015-2-11 16:56:11”,
“text”: “Subject”,
“description”: “The Description”,
“Subject”: null,
“Location”: “Location”,
“Description”: null,
“StartTime”: “0001-01-01T00:00:00”,
“EndTime”: “0001-01-01T00:00:00”,
“AllDayEvent”: false,
“Color”: null,
“CreatedBy”: null,
“CreatedOn”: “0001-01-01T00:00:00”,
“EventTypeId”: 0,
“AssignedTo”: null,
“ForId”: null,
“EventType”: null,
“Id”: 12,
“IsDeleted”: false,
“Timestamp”: null

Also, why does my calendar open in march instead of Feb?

make sure you’ve added dhtmlxscheduler_editors.js to the page:

Months are zero-based in JS,
0 is for January,
11 is for December

Thanks, must have missed that bit! Easy enough to fix :slight_smile: