diff --git a/activation.cpp b/activation.cpp
index 7cd31b22cc..15bfc8ada9 100644
--- a/activation.cpp
+++ b/activation.cpp
@@ -411,8 +411,19 @@ void Workspace::gotFocusIn( const Client* c )
 // session_active -> the window was active when saving session
 bool Workspace::allowClientActivation( const Client* c, Time time, bool focus_in, bool session_active )
     {
-    if( session_saving )
+    // options->focusStealingPreventionLevel :
+    // 0 - none    - old KWin behaviour, new windows always get focus
+    // 1 - low     - focus stealing prevention is applied normally, when unsure, activation is allowed
+    // 2 - normal  - focus stealing prevention is applied normally, when unsure, activation is not allowed,
+    //              this is the default
+    // 3 - high    - new window gets focus only if it belongs to the active application,
+    //              or when no window is currently active
+    // 4 - extreme - no window gets focus without user intervention
+    if( session_saving
+        && options->focusStealingPreventionLevel <= 3 ) // <= normal
+        {
         return true;
+        }
     Client* ac = activeClient();
     if( focus_in )
         {
@@ -422,6 +433,10 @@ bool Workspace::allowClientActivation( const Client* c, Time time, bool focus_in
         // got FocusOut, and therefore got deactivated.
         ac = last_active_client;
         }
+    if( options->focusStealingPreventionLevel == 0 ) // none
+        return true;
+    if( options->focusStealingPreventionLevel == 5 ) // extreme
+        return false;
     if( ac == NULL || ac->isDesktop())
         {
         kdDebug( 1212 ) << "Activation: No client active, allowing" << endl;
@@ -435,17 +450,22 @@ bool Workspace::allowClientActivation( const Client* c, Time time, bool focus_in
         kdDebug( 1212 ) << "Activation: Belongs to active application" << endl;
         return true;
         }
+    if( options->focusStealingPreventionLevel == 4 ) // high
+        return false;
     if( time == -1U )  // no time known
         if( session_active )
             return !was_user_interaction; // see Client::readUserTimeMapTimestamp()
         else
         {
         kdDebug() << "Activation: No timestamp at all" << endl;
-            // no timestamp at all, don't activate - because there's also creation timestamp
-            // done on CreateNotify, this case should happen only in case application
-            // maps again already used window, i.e. this won't happen after app startup
+        if( options->focusStealingPreventionLevel == 1 ) // low
+            return true;
+        // no timestamp at all, don't activate - because there's also creation timestamp
+        // done on CreateNotify, this case should happen only in case application
+        // maps again already used window, i.e. this won't happen after app startup
         return false; 
         }
+    // options->focusStealingPreventionLevel == 2 // normal
     Time user_time = ac->userTime();
     kdDebug( 1212 ) << "Activation, compared:" << time << ":" << user_time
         << ":" << ( timestampCompare( time, user_time ) >= 0 ) << endl;
diff --git a/kcmkwin/kwinoptions/windows.cpp b/kcmkwin/kwinoptions/windows.cpp
index efeae09727..89f04b514f 100644
--- a/kcmkwin/kwinoptions/windows.cpp
+++ b/kcmkwin/kwinoptions/windows.cpp
@@ -39,6 +39,7 @@
 #include <kapplication.h>
 #include <kdialog.h>
 #include <dcopclient.h>
+#include <kglobal.h>
 
 #include <X11/X.h>
 #include <X11/Xlib.h>
@@ -66,6 +67,7 @@
 #define KWIN_ROLL_OVER_DESKTOPS    "RollOverDesktops"
 #define KWIN_SHADEHOVER            "ShadeHover"
 #define KWIN_SHADEHOVER_INTERVAL   "ShadeHoverInterval"
+#define KWIN_FOCUS_STEALING        "FocusStealingPreventionLevel"
 
 // kwm config keywords
 #define KWM_ELECTRIC_BORDER                  "ElectricBorders"
@@ -511,6 +513,38 @@ KAdvancedConfig::KAdvancedConfig (bool _standAlone, KConfig *_config, QWidget *p
 
     lay->addWidget(electricBox);
 
+    QHBoxLayout* focusStealingLayout = new QHBoxLayout( this, KDialog::marginHint(), KDialog::spacingHint());
+    QLabel* focusStealingLabel = new QLabel( i18n( "Focus Stealing Prevention Level:" ), this );
+    focusStealing = new QComboBox( this );
+    focusStealing->insertItem( i18n( "Focus Stealing Prevention Level", "None" ));
+    focusStealing->insertItem( i18n( "Focus Stealing Prevention Level", "Low" ));
+    focusStealing->insertItem( i18n( "Focus Stealing Prevention Level", "Normal" ));
+    focusStealing->insertItem( i18n( "Focus Stealing Prevention Level", "High" ));
+    focusStealing->insertItem( i18n( "Focus Stealing Prevention Level", "Extreme" ));
+    focusStealingLabel->setBuddy( focusStealing );
+    focusStealingLayout->addWidget( focusStealingLabel );
+    focusStealingLayout->addWidget( focusStealing, AlignLeft );
+    wtstr = i18n( "This option specifies how much will KWin try to prevent unwanted focus stealing "
+                  "caused by unexpected activation of new windows.<ul>"
+                  "<li><em>None:</em> The standard old behaviour - prevention is turned off "
+                  "and new windows get always activated.</li>"
+                  "<li><em>Low:</em> Prevention is enabled; when some window doesn't have support "
+                  "for the underlying mechanism and KWin cannot reliably decide whether to "
+                  "activate the window or not, it will be activated. This setting may have both"
+                  "worse and better results than normal level depending on the applications.</li>"
+                  "<li><em>Normal:</em> Prevention is enabled; the default setting.</li>"
+                  "<li><em>High:</em> New windows get activated only if no window is currently active "
+                  "or if they belong to the currently active application. This setting is probably "
+                  "not really usable when noting using mouse focus policy.</li>"
+                  "<li><em>Extreme:</em> All windows must be explicitly activated by the user.</li>"
+                  "</ul>" );
+    QWhatsThis::add( focusStealing, wtstr );
+    QWhatsThis::add( focusStealingLabel, wtstr );
+
+    connect(focusStealing, SIGNAL(activated(int)), SLOT(changed()));
+    
+    lay->addLayout( focusStealingLayout );
+
     lay->addStretch();
     load();
 
@@ -538,6 +572,11 @@ void KAdvancedConfig::setAnimateShade(bool a) {
     animateShade->setChecked(a);
 }
 
+void KAdvancedConfig::setFocusStealing(int l) {
+    l = KMAX( 0, KMIN( 4, l ));
+    focusStealing->setCurrentItem(l);
+}
+
 void KAdvancedConfig::load( void )
 {
     config->setGroup( "Windows" );
@@ -548,6 +587,9 @@ void KAdvancedConfig::load( void )
 
     setElectricBorders(config->readNumEntry(KWM_ELECTRIC_BORDER, false));
     setElectricBorderDelay(config->readNumEntry(KWM_ELECTRIC_BORDER_DELAY, 150));
+
+    setFocusStealing( config->readNumEntry(KWIN_FOCUS_STEALING, 2 ));
+
     setChanged(false);
 }
 
@@ -568,6 +610,8 @@ void KAdvancedConfig::save( void )
 
     config->writeEntry(KWM_ELECTRIC_BORDER, getElectricBorders());
     config->writeEntry(KWM_ELECTRIC_BORDER_DELAY,getElectricBorderDelay());
+    
+    config->writeEntry(KWIN_FOCUS_STEALING, focusStealing->currentItem());
 
     if (standAlone)
     {
@@ -586,6 +630,7 @@ void KAdvancedConfig::defaults()
     setShadeHoverInterval(250);
     setElectricBorders(0);
     setElectricBorderDelay(150);
+    setFocusStealing(2);
     setChanged(true);
 }
 
diff --git a/kcmkwin/kwinoptions/windows.h b/kcmkwin/kwinoptions/windows.h
index 0cd63aea2b..40afa7c015 100644
--- a/kcmkwin/kwinoptions/windows.h
+++ b/kcmkwin/kwinoptions/windows.h
@@ -213,6 +213,10 @@ private:
   QRadioButton *active_move;
   QRadioButton *active_always;
   KIntNumInput *delays;
+  
+  void setFocusStealing( int );
+
+  QComboBox* focusStealing;
 };
 
 #endif
diff --git a/options.cpp b/options.cpp
index c6065445aa..d33294e2ef 100644
--- a/options.cpp
+++ b/options.cpp
@@ -62,6 +62,9 @@ unsigned long Options::updateSettings()
         altTabStyle = CDE;
 
     rollOverDesktops = config->readBoolEntry("RollOverDesktops", TRUE);
+    
+    focusStealingPreventionLevel = config->readNumEntry( "FocusStealingPreventionLevel", 2 );
+    focusStealingPreventionLevel = KMAX( 0, KMIN( 4, focusStealingPreventionLevel ));
 
     KConfig *gc = new KConfig("kdeglobals", false, false);
     bool isVirtual = KApplication::desktop()->isVirtualDesktop();
diff --git a/options.h b/options.h
index 4148e8f1a4..dbd3eaf881 100644
--- a/options.h
+++ b/options.h
@@ -180,6 +180,9 @@ class Options : public KDecorationOptions
          */
         bool rollOverDesktops;
 
+        // 0 - 4 , see Workspace::allowClientActivation()
+        int focusStealingPreventionLevel;
+
         /**
          * List of window classes to ignore PPosition size hint
          */