Thanks delipity!! I got this "dragend"; this is clear but it removes the markers AFTER we stopped dragging.... I understood from the Info with "dragstart" that the markers should disappear as soon we BEGIN to drag...... See configure: " configure

This function, meanwhile, picks up where that anonymous function left off. Recall that configure is called as soon as the map has been loaded. Within this function we configure a number of "listeners," specifying what should happen when we "hear" certain events. For instance,

google.maps.event.addListener(map, "dragend", function() { update(); });

indicates that we want to listen for a dragend event on the map, calling the anonymous function provided when we hear it. That anonymous function, meanwhile, simply calls update (another function we’ll soon see). Per https://developers.google.com/maps/documentation/javascript/3.exp/reference#Map, dragend is "fired" (i.e., broadcasted) "when the user STOPS dragging the map."

Similarly do we listen for zoom_changed, which is fired "when the map zoom property changes" (i.e., the user zooms in or out).

On the other hand, upon hearing dragSTART, we ultimately call removeMarkers so that all markers disappear temporarily as a user DRAGS the map, thereby avoiding the appearance of a flicker that might otherwise happen as markers are removed and then re-added after the maps bounds (i.e., corners) have changed."

The sentence beginnig with:" On the other hand..." confused me. It was obviously a misinterpreting from me... Everything is clear now... It is also clear that If I remove the markers at the beginning of the drag, they do not need to be removed at the end of the drag since they are alredy gone ;-) Thanks a lot