Add a configuation parameter in mapdhtml (something like 
DELAYDRAW="[true|false]") that allows to output map files to temprary files 
instead of calling the drawmap.php when the page loads.

This change seems to solve a esoteric bug in IE where sometimes the map is not 
rendered.

here is an e-mail sent about the situation/solution :

The changes are minmal : here is what I did :

  1) MapDHTML.widget.php : in function GetJavascriptVariables (around line 
468) :
   comment the 3 lines and add the 3 additional lines :

     //$url = WEBCOMMON."/wrapper/drawmap.php?
map_session_mode=$nMapSessionMode&run_query=0&".SID.$szFatalImage;
        //if (!$bCWCJSAPI)
        //$url .= "&dummy=".urlencode(microtime());

        $oMap = $this->moMapObject->oMap;

        $img = $oMap->draw();
        $url = $img->saveWebImage();

  2) in MapDHTML.js : function MapLayerDivImgOnLoad

    comment the line : //url = url + "&UniqId="+unique; 

 AFAIK : this chaneg does not affect any widgets except the Query widget when 
using the persistent results anf highlight results. Maybe Paul knows more 
about other widgets.