Add a small tolerance when testing pointer event positions

src/ol/mapbrowsereventhandler.js

@@ -241,11 +241,9 @@ ol.MapBrowserEventHandler.prototype.handlePointerDown_ = function(pointerEvent)
  * @private
  */
 ol.MapBrowserEventHandler.prototype.handlePointerMove_ = function(pointerEvent) {
-  // Fix IE10 on windows Surface : When you tap the tablet, it triggers
-  // multiple pointermove events between pointerdown and pointerup with
-  // the exact same coordinates of the pointerdown event. To avoid a
-  // 'false' touchmove event to be dispatched , we test if the pointer
-  // effectively moved.
+  // Between pointerdown and pointerup, pointermove events are triggered.
+  // To avoid a 'false' touchmove event to be dispatched, we test if the pointer
+  // moved a significant distance.
   if (this.isMoving_(pointerEvent)) {
     this.dragging_ = true;
     var newEvent = new ol.MapBrowserPointerEvent(
@@ -281,8 +279,8 @@ ol.MapBrowserEventHandler.prototype.relayEvent_ = function(pointerEvent) {
  * @private
  */
 ol.MapBrowserEventHandler.prototype.isMoving_ = function(pointerEvent) {
-  return pointerEvent.clientX != this.down_.clientX ||
-      pointerEvent.clientY != this.down_.clientY;
+  return Math.abs(pointerEvent.clientX - this.down_.clientX) > 0.75 ||
+      Math.abs(pointerEvent.clientY - this.down_.clientY) > 0.75;
 };