diff --git a/src/objectliterals.jsdoc b/src/objectliterals.jsdoc
index d8b12b7385..717416a1ba 100644
--- a/src/objectliterals.jsdoc
+++ b/src/objectliterals.jsdoc
@@ -487,9 +487,9 @@
 
  /**
  * @typedef {Object} olx.interaction.ModifyOptions
- * @property {ol.events.ConditionType} deleteCondition Condition that determines
- *     which event results in a vertex deletion. Default is a `singleclick`
- *     event with no modifier keys.
+ * @property {ol.events.ConditionType|undefined} deleteCondition Condition that
+ *     determines which event results in a vertex deletion. Default is a
+ *     `singleclick` event with no modifier keys.
  * @property {number|undefined} pixelTolerance Pixel tolerance for considering
  *     the pointer close enough to a segment or vertex for editing. Default is
  *     10 pixels.
diff --git a/src/ol/interaction/modifyinteraction.js b/src/ol/interaction/modifyinteraction.js
index 41024993d8..787905ef2a 100644
--- a/src/ol/interaction/modifyinteraction.js
+++ b/src/ol/interaction/modifyinteraction.js
@@ -3,6 +3,7 @@ goog.provide('ol.interaction.Modify');
 goog.require('goog.array');
 goog.require('goog.asserts');
 goog.require('goog.events');
+goog.require('goog.functions');
 goog.require('ol.Collection');
 goog.require('ol.CollectionEventType');
 goog.require('ol.Feature');
@@ -50,8 +51,10 @@ ol.interaction.Modify = function(options) {
    * @private
    */
   this.deleteCondition_ = goog.isDef(options.deleteCondition) ?
-      options.pixelTolerance : goog.functions.and(
-          ol.events.condition.noModifierKeys, ol.events.condition.singleClick);
+      options.deleteCondition :
+      /** @type {ol.events.ConditionType} */ (goog.functions.and(
+          ol.events.condition.noModifierKeys,
+          ol.events.condition.singleClick));
 
   /**
    * Editing vertex.
@@ -643,7 +646,8 @@ ol.interaction.Modify.prototype.insertVertex_ = function(segmentData, vertex) {
 ol.interaction.Modify.prototype.removeVertex_ = function() {
   var dragSegments = this.dragSegments_;
   var segmentsByFeature = {};
-  var component, coordinates, deleted, dragSegment, geometry, i, index, left;
+  var deleted = false;
+  var component, coordinates, dragSegment, geometry, i, index, left;
   var newIndex, newSegment, right, segmentData, uid;
   for (i = dragSegments.length - 1; i >= 0; --i) {
     dragSegment = dragSegments[i];