diff --git a/calendar/prototypes/wcap/sun-calendar-event-dialog-attendees.xml b/calendar/prototypes/wcap/sun-calendar-event-dialog-attendees.xml
index 740edb063b33..ea4534cd6820 100644
--- a/calendar/prototypes/wcap/sun-calendar-event-dialog-attendees.xml
+++ b/calendar/prototypes/wcap/sun-calendar-event-dialog-attendees.xml
@@ -96,11 +96,9 @@
       <field name="mIsOffline">0</field>
       <field name="mLDAPSession">null</field>
       <field name="mSessionAdded">0</field>
-      <field name="mOwnerID">null</field>
-      <field name="mUserID">null</field>
       <field name="mOrganizerID">null</field>
       <field name="mIsReadOnly">false</field>
-      <field name="mIsOrganizer">false</field>
+      <field name="mIsInvitation">false</field>
       <field name="mPopupOpen">false</field>
 
       <constructor>
@@ -191,24 +189,15 @@
 
             // assume we're the organizer [in case that the calendar
             // does not support the concept of identities].
-            this.mIsOrganizer = true;
-            
-            try {
-              this.mUserID = "";
-              this.mOwnerID = "";
-              this.mOrganizerID = "";
-            
-              var provider = calendar.QueryInterface(Components.interfaces.calIWcapCalendar);
-              this.mOwnerID = provider.ownerId;
-              this.mUserID = provider.session.userId;
-              this.mOrganizerID = ((organizer == null || organizer.id == null)
-                              ? this.mOwnerID // sensible default
-                              : organizer.id);
+            this.mIsInvitation = false;
 
-              // set 'mIsOrganizer' if the current calid originally scheduled this event.
-              this.mIsOrganizer = false;
-              if(this.mOwnerID == this.mOrganizerID)
-                this.mIsOrganizer = true;
+            this.mOrganizerID = "";
+            try {
+              var provider = calendar.QueryInterface(Components.interfaces.calIWcapCalendar);
+              this.mIsInvitation = provider.isInvitation(args.item);
+              this.mOrganizerID = ((organizer == null || organizer.id == null)
+                              ? provider.ownerId // sensible default
+                              : organizer.id);
             }
             catch(e) {}
 
@@ -216,9 +205,23 @@
             var template = document.getAnonymousElementByAttribute(this, "anonid", "item");
             template.focus();
 
-            if(this.mIsReadOnly || !this.mIsOrganizer)
+            if(this.mIsReadOnly || this.mIsInvitation)
               listbox.setAttribute("disabled","true");
             
+            // TODO: use calIWcapCalendar::owner
+            // TODO: use calIWcapCalendar::owner
+            // TODO: use calIWcapCalendar::owner
+            // TODO: use calIWcapCalendar::owner
+            // TODO: use calIWcapCalendar::owner
+            // TODO: use calIWcapCalendar::owner
+            // TODO: use calIWcapCalendar::owner
+            // TODO: use calIWcapCalendar::owner
+            // TODO: use calIWcapCalendar::owner
+            // TODO: use calIWcapCalendar::owner
+            // TODO: use calIWcapCalendar::owner
+            // TODO: use calIWcapCalendar::owner
+            // TODO: use calIWcapCalendar::owner
+            
             // TODO: the organizer should show up in the attendee list, but this information
             // should be based on the organizer contained in the appropriate field of calIItemBase.
             // This is currently not supported, since we're still missing calendar identities.
@@ -238,8 +241,7 @@
               }
               try {
                 var provider = calendar.QueryInterface(Components.interfaces.calIWcapCalendar);
-                var organizerCalendar = provider.session.getCalendarByCalId(this.mOrganizerID);
-                var props = organizerCalendar.getCalendarProperties("X-S1CS-CALPROPS-COMMON-NAME",{});
+                var props = provider.getCalendarProperties("X-S1CS-CALPROPS-COMMON-NAME",{});
                 if(props.length > 0)
                     organizer.commonName = props[0];
               }
@@ -314,7 +316,7 @@
           input.removeAttribute("disabled");
           icon.removeAttribute("disabled");
 
-          if(this.mIsReadOnly || !this.mIsOrganizer) {
+          if(this.mIsReadOnly || this.mIsInvitation) {
             input.setAttribute("disabled","true");
             icon.setAttribute("disabled","true");
           }
@@ -412,7 +414,7 @@
               input.removeAttribute("disabled");
               icon.removeAttribute("disabled");
 
-              if(this.mIsReadOnly || !this.mIsOrganizer) {
+              if(this.mIsReadOnly || this.mIsInvitation) {
                 input.setAttribute("disabled","true");
                 icon.setAttribute("disabled","true");
               }
@@ -1335,7 +1337,7 @@
             return;
           }
 
-          if(this.mIsReadOnly || !this.mIsOrganizer)
+          if(this.mIsReadOnly || this.mIsInvitation)
             return;
         
           if (event.originalTarget == null ||
@@ -1364,7 +1366,7 @@
 
       <handler event="keydown">
         <![CDATA[
-        if(this.mIsReadOnly || !this.mIsOrganizer)
+        if(this.mIsReadOnly || this.mIsInvitation)
           return;
         if(event.originalTarget.localName == "input") {
             switch(event.keyCode) {
@@ -1393,7 +1395,7 @@
         // appropriately and stop the event propagation.
         if(this.mPopupOpen)
           return;
-        if(this.mIsReadOnly || !this.mIsOrganizer)
+        if(this.mIsReadOnly || this.mIsInvitation)
           return;
         if(event.originalTarget.localName == "input") {
           switch(event.keyCode) {
@@ -1998,11 +2000,8 @@
       <field name="mStartHourDefault">8</field>
       <field name="mEndHourDefault">19</field>
 
-      <field name="mOwnerID">null</field>
-      <field name="mUserID">null</field>
-      <field name="mOrganizerID">null</field>
       <field name="mIsReadOnly">false</field>
-      <field name="mIsOrganizer">false</field>
+      <field name="mIsInvitation">false</field>
       <field name="mIgnoreUpdate">false</field>
       <field name="mDisplayTimezone">true</field>
 
@@ -2754,40 +2753,17 @@
 
             // assume we're the organizer [in case that the calendar
             // does not support the concept of identities].
-            this.mIsOrganizer = true;
+            this.mIsInvitation = false;
 
             //var organizerRow = document.getAnonymousElementByAttribute(this, "anonid", "event-organizer-row");
             //organizerRow.setAttribute("collapsed","true");
 
             try {
-              this.mUserID = "";
-              this.mOwnerID = "";
-              this.mOrganizerID = "";
-            
-              var provider = calendar.QueryInterface(Components.interfaces.calIWcapCalendar);
-              this.mOwnerID = provider.ownerId;
-              this.mUserID = provider.session.userId;
-              this.mOrganizerID = ((organizer == null || organizer.id == null)
-                              ? this.mOwnerID // sensible default
-                              : organizer.id);
-
-              // set 'mIsOrganizer' if the current calid originally scheduled this event.
-              this.mIsOrganizer = false;
-              if(this.mOwnerID == this.mOrganizerID)
-                this.mIsOrganizer = true;
-
-              // display the organizer [try to get the common name from the calid]
-              //TODO: either remove this row or enable this again -> organizerRow.removeAttribute("collapsed");
-              var organizer = document.getAnonymousElementByAttribute(this, "anonid", "event-organizer");
-              organizer.value = this.mOrganizerID;
-              var organizerCalendar = provider.session.getCalendarByCalId(this.mOrganizerID);
-              var props = organizerCalendar.getCalendarProperties("X-S1CS-CALPROPS-COMMON-NAME",{});
-              if(props.length > 0)
-                  organizer.value = props[0];
+              this.mIsInvitation = provider.isInvitation(args.item);
             }
             catch(e) {}
             
-            if(this.mIsReadOnly || !this.mIsOrganizer) {
+            if(this.mIsReadOnly || this.mIsInvitation) {
               document.getAnonymousElementByAttribute(this, "anonid", "next-slot").setAttribute('disabled', 'true');
               document.getAnonymousElementByAttribute(this, "anonid", "previous-slot").setAttribute('disabled', 'true');
             }            
diff --git a/calendar/prototypes/wcap/sun-calendar-event-dialog-freebusy.xml b/calendar/prototypes/wcap/sun-calendar-event-dialog-freebusy.xml
index 6a55e50128cf..5940a7f28a4e 100644
--- a/calendar/prototypes/wcap/sun-calendar-event-dialog-freebusy.xml
+++ b/calendar/prototypes/wcap/sun-calendar-event-dialog-freebusy.xml
@@ -896,10 +896,10 @@
             
               // first of all make sure that the given intervall is
               // within the intervall we're currently displaying.
-              if(entry.isBusyEntry) {
+              if(true) {
               
-                var rangeStart = entry.dtRangeStart.getInTimezone(kDefaultTimezone);
-                var rangeEnd = entry.dtRangeEnd.getInTimezone(kDefaultTimezone);
+                var rangeStart = entry.start.getInTimezone(kDefaultTimezone);
+                var rangeEnd = entry.end.getInTimezone(kDefaultTimezone);
                 rangeStart.normalize();
                 rangeEnd.normalize();
                 
@@ -1038,10 +1038,10 @@
               
                 // first of all make sure that the given intervall is
                 // within the intervall we're currently displaying.
-                if(entry.isBusyEntry) {
+                if(true) {
                 
-                  var rangeStart = entry.dtRangeStart.getInTimezone(kDefaultTimezone);
-                  var rangeEnd = entry.dtRangeEnd.getInTimezone(kDefaultTimezone);
+                  var rangeStart = entry.start.getInTimezone(kDefaultTimezone);
+                  var rangeEnd = entry.end.getInTimezone(kDefaultTimezone);
                   rangeStart.normalize();
                   rangeEnd.normalize();
 
@@ -1147,8 +1147,8 @@
       <field name="mMaxFreeBusy">0</field>
       <field name="mCalendar">null</field>
       <field name="mConsoleService">null</field>
-      <field name="mFreeBusySequence">0</field>
       <field name="mFreeBusy">null</field>
+      <field name="mPendingRequests">null</field>
       <field name="mStartDate">null</field>
       <field name="mEndDate">null</field>
       <field name="mScrollOffset">0</field>
@@ -1245,13 +1245,10 @@
             return this;
           },
   
-          onGetFreeBusyTimes: function(rc,requestId,calId,count,entries) {
+          onRequestResult: function(request,entries) {
 
-            if (rc == Components.results.NS_OK) {
-
-              // delegate to the binding
-              this.binding.onFreeBusy(requestId,calId,count,entries);
-            }
+            // delegate to the binding
+            this.binding.onFreeBusy(request,entries);
           }
         })
       ]]>
@@ -1266,12 +1263,14 @@
           this.mRange = Number(this.getAttribute("range"));
         
           this.mMaxFreeBusy = 0;
-          this.mFreeBusySequence = 0;
           this.mFreeBusy = [];
+          this.mPendingRequests = [];
 
           var self = this;
           var load = function loadHandler() { self.onLoad(); };
           window.addEventListener("load", load, true);
+          var unload = function unloadHandler() { self.onUnload(); };
+          window.addEventListener("unload", unload, true);
           
           this.mConsoleService = Components.classes["@mozilla.org/consoleservice;1"].getService(Components.interfaces.nsIConsoleService);
         ]]>
@@ -1287,7 +1286,7 @@
           <![CDATA[
           this.mStartDate = val.clone();
           this.mStartDate.makeImmutable();
-          for (i=1; i <= this.mMaxFreeBusy; i++) {
+          for (var i=1; i <= this.mMaxFreeBusy; i++) {
             this.getFreeBusyElement(i).startDate = val;
           }
           return val;
@@ -1305,7 +1304,7 @@
           <![CDATA[
           this.mEndDate = val.clone();
           this.mEndDate.makeImmutable();
-          for (i=1; i <= this.mMaxFreeBusy; i++) {
+          for (var i=1; i <= this.mMaxFreeBusy; i++) {
             this.getFreeBusyElement(i).endDate = val;
           }
           return val;
@@ -1329,6 +1328,20 @@
         </body>
       </method>
 
+      <method name="onUnload">
+        <body>
+          <![CDATA[
+            // cancel pending free/busy requests
+            for each(var request in this.mPendingRequests) {
+              request.cancel(null);
+            }
+
+            this.mFreeBusy = [];
+            this.mPendingRequests = [];
+          ]]>
+        </body>
+      </method>
+
       <method name="onInitialize">
         <body>
           <![CDATA[
@@ -1506,10 +1519,9 @@
                                "### " + (msg ? msg : ""));
                     this.mConsoleService.logStringMessage(str);
                                             
-                    this.mFreeBusy.push(i);
-                    this.mFreeBusySequence = this.mFreeBusy.length-1;
-                    
-                    this.mCalendar.session.getFreeBusyTimes(calid,start,end,true,this.mFreeBusyListener,true,this.mFreeBusySequence);
+                    var request = this.mCalendar.session.getFreeBusyTimes(calid,start,end,true,this.mFreeBusyListener);
+                    this.mFreeBusy[request.id] = i;
+                    this.mPendingRequests.push(request);
                   }
                 }
                 catch (ex) {
@@ -1523,26 +1535,32 @@
 
       <!-- onFreeBusy(), called with the result set from getFreeBusyTimes() -->
       <method name="onFreeBusy">
-        <parameter name="sequenceId"/>
-        <parameter name="calId"/>
-        <parameter name="count"/>
+        <parameter name="request"/>
         <parameter name="entries"/>
         <body>
           <![CDATA[
-            var row = this.mFreeBusy[sequenceId];
+            // find request in list of pending requests and remove from queue
+            var queue = this.mPendingRequests;
+            for(var i=0; i<queue.length; i++) {
+              if(queue[i] == request) {
+                queue.splice(i,1);
+                break;
+              }
+            }
 
-            var msg = "response for <"+calId+"> on row <"+row+"> - sequence <"+sequenceId+">";
-            var str = ("\n### freebusy log " + new Date() +
-                       "### " + (msg ? msg : ""));
-            this.mConsoleService.logStringMessage(str);
-
-            if(row) {
-              var freebusy = this.getFreeBusyElement(row);
-              var fieldValue = freebusy.getAttribute("calid");
-              if (fieldValue.indexOf(calId) == 0) {
+            if (request.status == Components.results.NS_OK) {
+              var row = this.mFreeBusy[request.id];
+              if(row) {
+                var freebusy = this.getFreeBusyElement(row);
                 freebusy.onFreeBusy(entries);
               }
             }
+
+            // reset map<row-id,request-id> if currently no further
+            // requests are pending. this basically shrinks the array
+            // in order to get rid of all previously remembered relationships.
+            if(!queue.length)
+              this.mFreeBusy = [];
           ]]>
         </body>
       </method>
diff --git a/calendar/prototypes/wcap/sun-calendar-event-dialog.js b/calendar/prototypes/wcap/sun-calendar-event-dialog.js
index 611565ce305a..ba3a89acba2d 100644
--- a/calendar/prototypes/wcap/sun-calendar-event-dialog.js
+++ b/calendar/prototypes/wcap/sun-calendar-event-dialog.js
@@ -50,7 +50,6 @@ var gItemDuration = null;
 var gStartTimezone = null;
 var gEndTimezone = null;
 var gIsReadOnly = false;
-var gOwnerID = null;
 var gUserID = null;
 var gOrganizerID = null;
 var gPrivacy = null;
@@ -1551,6 +1550,7 @@ function editAttendees()
   args.attendees = window.attendees;
   args.organizer = window.organizer;
   args.calendar = calendar;
+  args.item = window.calendarItem;
   args.onOk = callback;
   args.fbWrapper = window.fbWrapper;
 
@@ -1775,30 +1775,9 @@ function updateCalendar()
   var item = window.calendarItem;
   var calendar = document.getElementById("item-calendar").selectedItem.calendar;
 
-  // set 'gIsReadOnly' if the calendar is read-only
-  gIsReadOnly = false;
-  if (calendar && calendar.readOnly) {
-    gIsReadOnly = true;
-  } else {
-  
-    try {
-      var userID = "";
-      var ownerID = "";
-      var organizerID = "";
-    
-      var organizer = window.organizer;
-      var provider = calendar.QueryInterface(Components.interfaces.calIWcapCalendar);
-      ownerID = provider.ownerId;
-      userID = provider.session.userId;
-      organizerID = ((organizer == null || organizer.id == null)
-                      ? ownerID // sensible default
-                      : organizer.id);
-
-      if(ownerID != organizerID)
-        gIsReadOnly = true;
-    }
-    catch(e) {}
-  }
+  gIsReadOnly = true;
+  if(calendar)
+      gIsReadOnly = calendar.readOnly;
 
   // update the accept button
   updateAccept();