diff --git a/client.cpp b/client.cpp
index b9b4fe7a6b..3641c367bc 100644
--- a/client.cpp
+++ b/client.cpp
@@ -128,6 +128,8 @@ Client::Client( Workspace* ws )
     , demandAttentionKNotifyTimer( NULL )
     , paintRedirector( 0 )
     , electricMaximizing( false )
+    , activitiesDefined( false )
+    , needsSessionInteract(false)
     { // TODO: Do all as initialization
     
     scriptCache = new QHash<QScriptEngine*, ClientResolution>();
@@ -1606,9 +1608,12 @@ void Client::updateActivities( bool includeTransients )
  * isOnDesktop() instead.
  */
 int Client::desktop() const
-    {
-    return desk;
+{
+    if (needsSessionInteract) {
+        return NET::OnAllDesktops;
     }
+    return desk;
+}
 
 /**
  * Returns the list of activities the client window is on.
@@ -1617,6 +1622,9 @@ int Client::desktop() const
  */
 QStringList Client::activities() const
     {
+    if (needsSessionInteract) {
+        return QStringList();
+    }
     return activityList;
     }
 
@@ -1646,7 +1654,8 @@ void Client::setOnAllActivities( bool on )
     if( on )
         {
         activityList.clear();
-        XDeleteProperty( display(), window(), atoms->activities );
+        XChangeProperty(display(), window(), atoms->activities, XA_STRING, 8,
+                        PropModeReplace, (const unsigned char *)"ALL", 3);
         updateActivities( true );
         }
     else
@@ -2247,9 +2256,25 @@ void Client::checkActivities()
     {
     QStringList newActivitiesList;
     QByteArray prop = getStringProperty(window(), atoms->activities);
-    if ( ! prop.isEmpty() )
-        newActivitiesList = QString(prop).split(',');
+    activitiesDefined = !prop.isEmpty();
+    if (prop == "ALL") {
+        //copied from setOnAllActivities to avoid a redundant XChangeProperty.
+        if (!activityList.isEmpty()) {
+            activityList.clear();
+            updateActivities( true );
+        }
+        return;
+    }
+    if (prop.isEmpty()) {
+        //note: this makes it *act* like it's on all activities but doesn't set the property to 'ALL'
+        if (!activityList.isEmpty()) {
+            activityList.clear();
+            updateActivities( true );
+        }
+        return;
+    }
 
+    newActivitiesList = QString(prop).split(',');
     if (newActivitiesList == activityList)
         return; //expected change, it's ok.
 
@@ -2272,6 +2297,11 @@ void Client::checkActivities()
     setOnActivities( newActivitiesList );
     }
 
+void Client::setSessionInteract(bool needed)
+{
+    needsSessionInteract = needed;
+}
+
 } // namespace
 
 #include "client.moc"
diff --git a/client.h b/client.h
index f8d67d3372..d36ab61582 100644
--- a/client.h
+++ b/client.h
@@ -400,6 +400,9 @@ class Client
 
         TabBox::TabBoxClientImpl* tabBoxClient() const { return m_tabBoxClient; }
 
+        //sets whether the client should be treated as a SessionInteract window
+        void setSessionInteract(bool needed);
+
     private slots:
         void autoRaise();
         void shadeHover();
@@ -694,6 +697,9 @@ class Client
         friend class SWrapper::Client;
 
         void checkActivities();
+        bool activitiesDefined; //whether the x property was actually set
+
+        bool needsSessionInteract;
     };
 
 /**
diff --git a/manage.cpp b/manage.cpp
index fbb531dad0..cd1e75dc9b 100644
--- a/manage.cpp
+++ b/manage.cpp
@@ -207,7 +207,7 @@ bool Client::manage( Window w, bool isMapped )
             desk = info->desktop(); // Window had the initial desktop property, force it
         if( desktop() == 0 && asn_valid && asn_data.desktop() != 0 )
             desk = asn_data.desktop();
-        if (!isMapped && !noborder && isNormalWindow() && isOnAllActivities()) {
+        if (!isMapped && !noborder && isNormalWindow() && !activitiesDefined) {
             //a new, regular window, when we're not recovering from a crash,
             //and it hasn't got an activity. let's try giving it the current one.
             //TODO: decide whether to keep this before the 4.6 release
@@ -551,10 +551,33 @@ bool Client::manage( Window w, bool isMapped )
         else
             allow = workspace()->allowClientActivation( this, userTime(), false );
 
-        // If session saving, force showing new windows (i.e. "save file?" dialogs etc.)
-        // also force if activation is allowed
-        if( !isOnCurrentDesktop() && !isMapped && !session && ( allow || workspace()->sessionSaving() ))
-            workspace()->setCurrentDesktop( desktop() );
+        if (!(isMapped || session)) {
+            if (workspace()->sessionSaving()) {
+                /*
+                 * If we get a new window during session saving, we assume it's some 'save file?' dialog
+                 * which the user really needs to see (to know why logout's stalled).
+                 * We also assume it'll be destroyed when it's done - we never unset this flag.
+                 *
+                 * Given the current session management protocol, I can't see a nicer way of doing this.
+                 * Someday I'd like to see a protocol that tells the windowmanager who's doing SessionInteract.
+                 */
+                needsSessionInteract = true;
+                //show the parent too
+                ClientList mainclients = mainClients();
+                for( ClientList::ConstIterator it = mainclients.constBegin();
+                    it != mainclients.constEnd(); ++it ) {
+                    (*it)->setSessionInteract(true);
+                }
+            } else if (allow) {
+                // also force if activation is allowed
+                if( !isOnCurrentDesktop() ) {
+                    workspace()->setCurrentDesktop( desktop() );
+                }
+                /*if (!isOnCurrentActivity()) {
+                    workspace()->setCurrentActivity( activities().first() );
+                } FIXME no such method*/
+            }
+        }
 
         bool belongs_to_desktop = false;
         for( ClientList::ConstIterator it = group()->members().constBegin();
diff --git a/sm.cpp b/sm.cpp
index ad3b5e2321..163fd403d4 100644
--- a/sm.cpp
+++ b/sm.cpp
@@ -134,6 +134,7 @@ void Workspace::storeSession( KConfig* config, SMSavePhase phase )
 
 void Workspace::storeClient( KConfigGroup &cg, int num, Client *c )
     {
+    c->setSessionInteract(false); //make sure we get the real values
     QString n = QString::number(num);
     cg.writeEntry( QString("sessionId")+n, c->sessionId().constData() );
     cg.writeEntry( QString("windowRole")+n, c->windowRole().constData() );
@@ -613,6 +614,15 @@ void SessionSaveDoneHelper::processData()
         IceProcessMessages( SmcGetIceConnection( conn ), 0, 0 );
     }
 
+void Workspace::sessionSaveDone()
+{
+    session_saving = false;
+    //remove sessionInteract flag from all clients
+    foreach( Client* c, clients ) {
+        c->setSessionInteract(false);
+    }
+}
+
 } // namespace
 
 #include "sm.moc"
diff --git a/workspace.h b/workspace.h
index 12ec259200..0eec15df34 100644
--- a/workspace.h
+++ b/workspace.h
@@ -1246,11 +1246,6 @@ inline void Workspace::sessionSaveStarted()
     session_saving = true;
     }
 
-inline void Workspace::sessionSaveDone()
-    {
-    session_saving = false;
-    }
-
 inline bool Workspace::sessionSaving() const
     {
     return session_saving;