Two sections over Tree are not displayed

Request for help with my project.
Have two sections that are loaded via three Json files.

			name:	"timeline",
			x_unit:	"day",
			x_step:	1,
			y_unit:	scheduler.serverList("data"),
  			y_property: "my",
			folder_events_available: false,
			second_scale: {
         		x_unit: "month",
         		x_date: "%F %Y"

Here I load the Json file

scheduler.config.check_limits = true;
	scheduler.config.now_date = new Date();

json1.json = data for the tree structure (scheduler.serverList(“data”))
json2.json are the data

Now the json data are read in, but are not displayed.

scheduler.attachEvent("onXLE", function () {
		var currentDataArr = [];
		for (var i = 0; i < dataArr.length; i++) {
		   currentDataArr push(dataArr[i]);
		scheduler.updateCollection("data", currentDataArr);

The Json data is correct, have checked this. They are handed over - the console shows me.
When I open the page, the data is displayed briefly. scheduler.updateCollection runs two times. The last time it is run, the data is deleted.

Does somebody has any idea?

Thank you
Best regards


Possibly data is not deleted, just hidden because of there are no events with section_id from updated currentDataArr. Please check it.
If the issue still occurs, any sample will be very useful to understand the cause.