timeline empty error

Hi, just to notify.

I have a timelineview with dhtmlxscheduler and when my timeline is empty (without sections) and i click on a empty space, an error occur:

“Uncaught TypeError: Cannot read property ‘children’ of undefined”

In the file: dhtmlxscheduler_treetimeline.js theres a listener to onCellClick event that
try to access an object in a empty array.

That y_unit array is empty

scheduler.attachEvent("onCellClick", function (x, y, a, b, event){
	if(scheduler._isRender("tree")) {
		if(!scheduler.matrix[scheduler._mode].folder_events_available) {
			if(typeof scheduler.matrix[scheduler._mode].y_unit[y].children != "undefined") {

Thans for the report
We will add fix for such corner case as part of the next build.