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

@@ -159,25 +159,28 @@ gantt.attachEvent("onGanttScroll", function (left, top){
   var left_date = gantt.dateFromPos(left)
   var right_date = gantt.dateFromPos(left + gantt.$task.offsetWidth)
   
-  gantt.config.start_date = gantt.config.start_date || gantt.getState().min_date;
-  gantt.config.end_date = gantt.config.end_date || gantt.getState().max_date;
-  
-  var min_allowed_date = gantt.date.add(gantt.config.start_date, 1, "day");
-  var max_allowed_date = gantt.date.add(gantt.config.end_date, -1, "day");
-
-  var repaint = false;
-  if (+left_date <= +min_allowed_date){
-    gantt.config.start_date = gantt.date.add(gantt.config.start_date, -1, "day");
-    repaint = true;
-  }
-  if (+right_date >= +max_allowed_date){
-    gantt.config.end_date = gantt.date.add(gantt.config.end_date, 1, "day");
-    repaint = true;
-  }
-  
-  if (repaint) {
-    setTimeout(function(){
-      gantt.render()
-    },20)
-  }
+  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;
+    
+    var min_allowed_date = gantt.date.add(gantt.config.start_date, 1, "day");
+    var max_allowed_date = gantt.date.add(gantt.config.end_date, -1, "day");
+    
+    var repaint = false;
+    if (+left_date <= +min_allowed_date){
+        gantt.config.start_date = gantt.date.add(gantt.config.start_date, -1, "day");
+        repaint = true;
+    }
+    if (+right_date >= +max_allowed_date){
+        gantt.config.end_date = gantt.date.add(gantt.config.end_date, 1, "day");
+        repaint = true;
+    }
+    
+    if (repaint) {
+        setTimeout(function(){
+            gantt.render()
+        },20)
+    }
+}
 });