diff --git a/HISTORY.md b/HISTORY.md
index 2d72dfd8..c7517237 100644
--- a/HISTORY.md
+++ b/HISTORY.md
@@ -27,6 +27,7 @@ http://visjs.org
 - Deprecated event `finishedRedraw` as it's redundant.
 - Renamed option `animate` to `animation`, and changed it to be either a boolean
   or an object `{duration: number, easingFunction: string}`.
+- Fixed #831: items losing selection when their type changed.
 
 ### Graph2d
 
diff --git a/lib/timeline/component/ItemSet.js b/lib/timeline/component/ItemSet.js
index 2395cb9a..0d8a96a4 100644
--- a/lib/timeline/component/ItemSet.js
+++ b/lib/timeline/component/ItemSet.js
@@ -818,11 +818,13 @@ ItemSet.prototype._onUpdate = function(ids) {
     var type = me._getType(itemData);
 
     var constructor = ItemSet.types[type];
+    var selected;
 
     if (item) {
       // update item
       if (!constructor || !(item instanceof constructor)) {
         // item type has changed, delete the item and recreate it
+        selected = item.selected; // preserve selection of this item
         me._removeItem(item);
         item = null;
       }
@@ -837,6 +839,10 @@ ItemSet.prototype._onUpdate = function(ids) {
         item = new constructor(itemData, me.conversion, me.options);
         item.id = id; // TODO: not so nice setting id afterwards
         me._addItem(item);
+        if (selected) {
+          this.selection.push(id);
+          item.select();
+        }
       }
       else if (type == 'rangeoverflow') {
         // TODO: deprecated since version 2.1.0 (or 3.0.0?). cleanup some day
@@ -847,7 +853,7 @@ ItemSet.prototype._onUpdate = function(ids) {
         throw new TypeError('Unknown item type "' + type + '"');
       }
     }
-  });
+  }.bind(this));
 
   this._order();
   this.stackDirty = true; // force re-stacking of all items next redraw