I just saw this:

http://code.google.com/p/gmaps-utility-library-dev/source/detail?r=1214

It appears the bug may have been addressed in r1214 which was just committed last week.

I’m going to check out 1214 now and see how it goes.

Cheers

http://maxb.net/blog/2010/03/15/markerclusterer-clearmarkers-bug-demo/

http://code.google.com/p/gmaps-utility-library-dev/issues/detail?id=196

Have you submitted this or a bug report to the project? The fact the documented call is not functional will likely hit others it would be great to see this fix incorporated.

see here
http://www.piemonteitalia.eu/index.php?option=com_mappet

the “main” of the application is here:
http://www.piemonteitalia.eu/components/com_mappet/views/mappet/js/mappet.js

when i submit the form I invoke processJson
in function “processJson” I call
markerCluster.destroy();

I hope I have been of help to you

...
 this.destroy = function() {
		this.clearMarkers();
		GEvent.removeListener(mcfn_);
		mcfn_ = null;
		me_ = null;
	}
...

but this.destroy get’s never called?

Faced few more issues after applying above patch. I was trying to clear the markers and readd them based on some criteria.Problem was after calling ‘destroy’ it removed the listener and never added it back.So for newly added markers cluster stopped redrawing itself.have fixed the issues as follows.

3.38 @@ -375,22 +379,43 @@
3.39 * @param {Array of GMarker} markers The markers you want to add.
3.40 */
3.41 this.addMarkers = function (markers) {
3.42 -
3.43 for (var i = 0; i < markers.length; ++i) {
3.44 this.addMarker(markers[i], true);
3.45 }
3.46 this.redraw_();
3.47 + //##neerjug fixed for clearMarkers.
3.48 + if (!mcfn_ || mcfn_=== null) {
3.49 + mcfn_ = GEvent.addListener(map_, "moveend", function(){
3.50 + me_.resetViewport();
3.51 + });
3.52 + }
3.53 };
3.54
3.55 // initialize
3.56 if (typeof opt_markers === "object" && opt_markers !== null) {
3.57 this.addMarkers(opt_markers);
3.58 +
3.59 }
3.60 + // when map move end, regroup.
3.61 + //neerjug modified.it was a bug. moveend was not behaving properly after clearmarkers if fired.
3.62 +// mcfn_ = GEvent.addListener(map_, "moveend", function(){
3.63 +// me_.resetViewport();
3.64 +// });
3.65 + //###max
3.66 + this.destroy = function(){
3.67 + this.clearMarkers();
3.68 + if (mcfn_ != null) {
3.69 + GEvent.removeListener(mcfn_);
3.70 + mcfn_ = null;
3.71 + //me_ = null;
3.72 + }
3.73 +
3.74 +
3.75 + }
3.76 + //###max
3.77
3.78 – // when map move end, regroup.
3.79 – mcfn_ = GEvent.addListener(map_, "moveend", function () {
3.80 – me_.resetViewport();
3.81 – });
3.82 + //##neerjug end of fixes for clear markers.
3.83 +
3.84 }

http://code.google.com/p/gmaps-utility-library-dev/source/browse/trunk/markerclusterer/src/markerclusterer.js

Thanks,
Neerju