MarkerClustererwill install the marker map in nullif it is in the cluster so that it no longer appears on the map. MarkerClustererthen it will return the marker card to mapany time when it is no longer in the cluster. You can try checking each of your markers:
var mapOptions = {
center: new google.maps.LatLng( 19, 19 ),
mapTypeId: google.maps.MapTypeId.ROADMAP };
map = new google.maps.Map( document.getElementById( "map_canvas" ), mapOptions );
var markerClusterer = new MarkerClusterer( map, markers, { ... });
google.maps.event.addListener( map, "idle", function() {
for ( var i = 0; i < markers.length; i++ ) {
var mrkr = markers[i];
if ( mrkr.getMap() != null ) {
mrkr.infobox.open();
}
else {
mrkr.infobox.close();
}
}
}
map.setZoom( 19 );
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