Default duration import & fix scroll event

edit-mode/function/ganttConfig.js

@@ -314,6 +314,9 @@ var allColumns = [
 				start_date: start,
 				end_date: end
 			})
+			if (todayDuration < 0) {
+				todayDuration = 0;
+			}
 			progress = todayDuration/endDuration * 100
 			return roundToTwo(progress);
 		}, resize: true

edit-mode/function/ganttEvent.js

@@ -159,6 +159,8 @@ gantt.attachEvent("onGanttScroll", function (left, top){
   var left_date = gantt.dateFromPos(left)
   var right_date = gantt.dateFromPos(left + gantt.$task.offsetWidth)
   
+  let taskCount = gantt.getTaskCount();
+  if (taskCount > 0) {
     gantt.config.start_date = gantt.config.start_date || gantt.getState().min_date;
     gantt.config.end_date = gantt.config.end_date || gantt.getState().max_date;
     
@@ -180,4 +182,5 @@ gantt.attachEvent("onGanttScroll", function (left, top){
             gantt.render()
         },20)
     }
+}
 });