diff --git a/client.cpp b/client.cpp
index 983f2d53cc..d460b1fd33 100644
--- a/client.cpp
+++ b/client.cpp
@@ -1540,7 +1540,8 @@ NET::WindowType Client::windowType( bool strict, int supported_types ) const
                 && abs( width() - workspace()->clientArea( FullArea, this ).width()) < 10 )
                 wt = NET::TopMenu;
             }
-        const char* const oo_prefix = "OpenOffice.org"; // QCString has no startsWith()
+        const char* const oo_prefix = "openoffice.org"; // QCString has no startsWith()
+        // oo_prefix is lowercase, because resourceClass() is forced to be lowercase
         if( qstrncmp( resourceClass(), oo_prefix, strlen( oo_prefix )) == 0 && wt == NET::Dialog )
             wt = NET::Normal; // see bug #66065
         if( wt == NET::Unknown ) // this is more or less suggested in NETWM spec
diff --git a/client.h b/client.h
index 2da3d09a34..d7bc560338 100644
--- a/client.h
+++ b/client.h
@@ -573,12 +573,12 @@ inline int Client::mappingState() const
 
 inline QCString Client::resourceName() const
     {
-    return resource_name;
+    return resource_name; // it is always lowercase
     }
 
 inline QCString Client::resourceClass() const
     {
-    return resource_class;
+    return resource_class; // it is always lowercase
     }
 
 inline
diff --git a/group.cpp b/group.cpp
index aafa51cb40..81aafb3ac2 100644
--- a/group.cpp
+++ b/group.cpp
@@ -204,14 +204,15 @@ void Workspace::checkTransients( Window w )
 //****************************************
 
 // hacks for broken apps here
+// all resource classes are forced to be lowercase
 bool Client::resourceMatch( const Client* c1, const Client* c2 )
     {
     // xv has "xv" as resource name, and different strings starting with "XV" as resource class
-    if( qstrncmp( c1->resourceClass(), "XV", 2 ) == 0 && c1->resourceName() == "xv" )
-         return qstrncmp( c2->resourceClass(), "XV", 2 ) == 0 && c2->resourceName() == "xv";
+    if( qstrncmp( c1->resourceClass(), "xv", 2 ) == 0 && c1->resourceName() == "xv" )
+         return qstrncmp( c2->resourceClass(), "xv", 2 ) == 0 && c2->resourceName() == "xv";
     // Mozilla has "Mozilla" as resource name, and different strings as resource class
-    if( c1->resourceName() == "Mozilla" )
-        return c2->resourceName() == "Mozilla";
+    if( c1->resourceName() == "mozilla" )
+        return c2->resourceName() == "mozilla";
     return c1->resourceClass() == c2->resourceClass();
     }
 
@@ -290,7 +291,7 @@ bool Client::sameAppWindowRoleMatch( const Client* c1, const Client* c2, bool ac
         ||
     // hacks here
         // Mozilla has resourceName() and resourceClass() swapped
-        c1->resourceName() == "Mozilla" && c2->resourceName() == "Mozilla" )
+        c1->resourceName() == "mozilla" && c2->resourceName() == "mozilla" )
         {
         if( !active_hack )   // without the active hack for focus stealing prevention,
             return c1 == c2; // different mainwindows are always different apps
diff --git a/manage.cpp b/manage.cpp
index 62c6ae82f5..c7f2b7d528 100644
--- a/manage.cpp
+++ b/manage.cpp
@@ -95,8 +95,10 @@ bool Client::manage( Window w, bool isMapped )
     XClassHint classHint;
     if ( XGetClassHint( qt_xdisplay(), client, &classHint ) ) 
         {
-        resource_name = classHint.res_name;
-        resource_class = classHint.res_class;
+        // Qt3.2 and older had this all lowercase, Qt3.3 capitalized resource class
+        // force lowercase, so that workarounds listing resource classes still work
+        resource_name = QCString( classHint.res_name ).lower();
+        resource_class = QCString( classHint.res_class ).lower();
         XFree( classHint.res_name );
         XFree( classHint.res_class );
         }
diff --git a/options.cpp b/options.cpp
index 661a68c2b1..e87124d83b 100644
--- a/options.cpp
+++ b/options.cpp
@@ -127,6 +127,16 @@ unsigned long Options::updateSettings()
 
     ignorePositionClasses = config->readListEntry("IgnorePositionClasses");
     ignoreFocusStealingClasses = config->readListEntry("IgnoreFocusStealingClasses");
+    // Qt3.2 and older had resource class all lowercase, but Qt3.3 has it capitalized
+    // therefore Client::resourceClass() forces lowercase, force here lowercase as well
+    for( QStringList::Iterator it = ignorePositionClasses.begin();
+         it != ignorePositionClasses.end();
+         ++it )
+        (*it) = (*it).lower();
+    for( QStringList::Iterator it = ignoreFocusStealingClasses.begin();
+         it != ignoreFocusStealingClasses.end();
+         ++it )
+        (*it) = (*it).lower();
 
     // Mouse bindings
     config->setGroup( "MouseBindings");
diff --git a/sm.cpp b/sm.cpp
index 41d56983e1..d07aac49de 100644
--- a/sm.cpp
+++ b/sm.cpp
@@ -161,7 +161,7 @@ void Workspace::loadSessionInfo()
         info->wmCommand = config->readEntry( QString("wmCommand")+n ).latin1();
         info->wmClientMachine = config->readEntry( QString("wmClientMachine")+n ).latin1();
         info->resourceName = config->readEntry( QString("resourceName")+n ).latin1();
-        info->resourceClass = config->readEntry( QString("resourceClass")+n ).latin1();
+        info->resourceClass = config->readEntry( QString("resourceClass")+n ).lower().latin1();
         info->geometry = config->readRectEntry( QString("geometry")+n );
         info->restore = config->readRectEntry( QString("restore")+n );
         info->fsrestore = config->readRectEntry( QString("fsrestore")+n );
@@ -195,7 +195,7 @@ void Workspace::loadFakeSessionInfo()
         fakeSession.append( info );
         info->windowRole = config->readEntry( QString("windowRole")+n ).latin1();
         info->resourceName = config->readEntry( QString("resourceName")+n ).latin1();
-        info->resourceClass = config->readEntry( QString("resourceClass")+n ).latin1();
+        info->resourceClass = config->readEntry( QString("resourceClass")+n ).lower().latin1();
         info->wmClientMachine = config->readEntry( QString("clientMachine")+n ).latin1();
         info->geometry = config->readRectEntry( QString("geometry")+n );
         info->restore = config->readRectEntry( QString("restore")+n );