Update ItemSet.js (#4238)

Delay the tooltip popup on items for 500ms.

lib/timeline/component/ItemSet.js

@@ -192,6 +192,7 @@ function ItemSet(body, options) {
   this.selection = [];  // list with the ids of all selected nodes
 
   this.popup = null;
+  this.popupTimer = null;
 
   this.touchParams = {}; // stores properties while dragging
   this.groupTouchParams = {};
@@ -480,6 +481,8 @@ ItemSet.prototype.markDirty = function(options) {
  * Destroy the ItemSet
  */
 ItemSet.prototype.destroy = function() {
+  this.clearPopupTimer();
+  
   this.hide();
   this.setItems(null);
   this.setGroups(null);
@@ -536,6 +539,29 @@ ItemSet.prototype.show = function() {
   }
 };
 
+/**
+ * Activates the popup timer to show the given popup after a fixed time.
+ */
+ItemSet.prototype.setPopupTimer = function (popup) {
+    this.clearPopupTimer();
+    if (popup) {
+      this.popupTimer = setTimeout(
+        function () {
+          popup.show()
+        }, 500);
+    }
+};
+
+/**
+ * Clears the popup timer for the tooltip.
+ */
+ItemSet.prototype.clearPopupTimer = function () {
+    if (this.popupTimer != null) {
+        clearTimeout(this.popupTimer);
+        this.popupTimer = null;
+    }
+};
+
 /**
  * Set selected items by their id. Replaces the current selection
  * Unknown id's are silently ignored.
@@ -1533,6 +1559,12 @@ ItemSet.prototype._onDragStartAddItem = function (event) {
  * @private
  */
 ItemSet.prototype._onDrag = function (event) {
+  // deactivate tooltip window
+  this.clearPopupTimer();
+  if (this.popup != null) {
+    this.popup.hide();
+  }
+  
   if (this.touchParams.itemProps) {
     event.stopPropagation();
 
@@ -2016,10 +2048,11 @@ ItemSet.prototype._onMouseOver = function (event) {
       event.clientX - util.getAbsoluteLeft(container) + container.offsetLeft,
       event.clientY - util.getAbsoluteTop(container) + container.offsetTop
     );
-    this.popup.show();
+    this.setPopupTimer(this.popup);
   } else {
     // Hovering over item without a title, hide popup
     // Needed instead of _just_ in _onMouseOut due to #2572
+    this.clearPopupTimer();
     if (this.popup != null) {
       this.popup.hide();
     }
@@ -2041,6 +2074,7 @@ ItemSet.prototype._onMouseOut = function (event) {
     return;
   }
 
+  this.clearPopupTimer();
   if (this.popup != null) {
     this.popup.hide();
   }
@@ -2054,6 +2088,11 @@ ItemSet.prototype._onMouseMove = function (event) {
   var item = this.itemFromTarget(event);
   if (!item) return;
 
+  if (this.popupTimer != null) {
+      // restart timer
+      this.setPopupTimer(this.popup);
+  }
+  
   if (this.options.showTooltips && this.options.tooltip.followMouse) {
     if (this.popup) {
       if (!this.popup.hidden) {