Same seems to happen here - the control center option has no effect

Same here with kdebase-3.5.2-1.2.fc4 from the kde-redhat repo. on my FC4 box.
Reverting back to kdebase-3.5.1 fixed the problem.

*** Bug 124841 has been marked as a duplicate of this bug. ***

I can confirm this on FreeBSD using FreeBSD ports. In KDE 3.5.1, I could
traverse windows on all desktops via alt+tab. On 3.5.2, this setting gets
ignored and I only see the windows on the current desktop.

another info :
when the list is not displayed AND the option to navigate on all desktop is activated (first option is disabled but second is enabled in the control center), the navigation shows all windows from all desktop.

So it seems that this is the windows list that is not complete.

Here is a bit of analysis on what is going on:
In SVN revision 514048, a separate focus chain for each desktop was introduced. The methods Workspace::nextFocusChainClient() and Workspace::previousFocusChainClient() (both in kdebase/kwin/tabbox.cpp) now only look for windows on the current desktop. Therefore, only windows from the current desktop appear in the alt-tab box. The easiest way to fix this problem would probably be to revert the two methods above to their old behavior - they should return windows from all desktops again. TabBox::createClientList() checks whether the returned window is on the desired desktop or not anyway.

SVN commit 528608 by lunakl:

Separate focus chains are nice, but KDE-style Alt+Tab not limited
to the current desktop still needs the global one for MRU.
BUG: 124721



 M  +15 -0     layers.cpp  
 M  +12 -14    tabbox.cpp  
 M  +9 -0      workspace.cpp  
 M  +1 -0      workspace.h  


--- branches/KDE/3.5/kdebase/kwin/layers.cpp #528607:528608
@@ -441,6 +441,21 @@
                 }
             }
       	}
+    // the same for global_focus_chain
+    if( c->wantsTabFocus() && global_focus_chain.contains( active_client ))
+        {
+        global_focus_chain.remove( c );
+        for( ClientList::Iterator it = global_focus_chain.fromLast();
+             it != global_focus_chain.end();
+             --it )
+            {
+            if( Client::belongToSameApplication( active_client, *it ))
+                {
+                global_focus_chain.insert( it, c );
+                break;
+                }
+            }
+      	}
     updateStackingOrder();
     }
 
--- branches/KDE/3.5/kdebase/kwin/tabbox.cpp #528607:528608
@@ -1168,14 +1168,13 @@
 */
 Client* Workspace::nextFocusChainClient( Client* c ) const
     {
-    int desktop = !c || c->isOnAllDesktops() ? currentDesktop() : c->desktop();
-    if ( focus_chain[desktop].isEmpty() )
+    if ( global_focus_chain.isEmpty() )
         return 0;
-    ClientList::ConstIterator it = focus_chain[desktop].find( c );
-    if ( it == focus_chain[desktop].end() )
-        return focus_chain[desktop].last();
-    if ( it == focus_chain[desktop].begin() )
-        return focus_chain[desktop].last();
+    ClientList::ConstIterator it = global_focus_chain.find( c );
+    if ( it == global_focus_chain.end() )
+        return global_focus_chain.last();
+    if ( it == global_focus_chain.begin() )
+        return global_focus_chain.last();
     --it;
     return *it;
     }
@@ -1186,15 +1185,14 @@
 */
 Client* Workspace::previousFocusChainClient( Client* c ) const
     {
-    int desktop = !c || c->isOnAllDesktops() ? currentDesktop() : c->desktop();
-    if ( focus_chain[desktop].isEmpty() )
+    if ( global_focus_chain.isEmpty() )
         return 0;
-    ClientList::ConstIterator it = focus_chain[desktop].find( c );
-    if ( it == focus_chain[desktop].end() )
-        return focus_chain[desktop].first();
+    ClientList::ConstIterator it = global_focus_chain.find( c );
+    if ( it == global_focus_chain.end() )
+        return global_focus_chain.first();
     ++it;
-    if ( it == focus_chain[desktop].end() )
-        return focus_chain[desktop].first();
+    if ( it == global_focus_chain.end() )
+        return global_focus_chain.first();
     return *it;
     }
 
--- branches/KDE/3.5/kdebase/kwin/workspace.cpp #528607:528608
@@ -564,6 +564,7 @@
          i <= numberOfDesktops();
          ++i )
         focus_chain[ i ].remove( c );
+    global_focus_chain.remove( c );
     attention_chain.remove( c );
     if( c->isTopMenu())
         removeTopMenu( c );
@@ -598,6 +599,7 @@
              i<= numberOfDesktops();
              ++i )
             focus_chain[i].remove(c);
+        global_focus_chain.remove( c );
         return;
         }
     if(c->desktop() == NET::OnAllDesktops)
@@ -631,6 +633,13 @@
                 focus_chain[ i ].remove( c );
             }
         }
+    if( make_first )
+        {
+        global_focus_chain.remove( c );
+        global_focus_chain.append( c );
+        }
+    else if( !global_focus_chain.contains( c ))
+        global_focus_chain.prepend( c );
     }
 
 void Workspace::updateCurrentTopMenu()
--- branches/KDE/3.5/kdebase/kwin/workspace.h #528607:528608
@@ -510,6 +510,7 @@
         ClientList unconstrained_stacking_order;
         ClientList stacking_order;
         QValueVector< ClientList > focus_chain;
+        ClientList global_focus_chain; // this one is only for things like tabbox's MRU
         ClientList should_get_focus; // last is most recent
         ClientList attention_chain;
         

*** Bug 125635 has been marked as a duplicate of this bug. ***

*** Bug 125532 has been marked as a duplicate of this bug. ***

*** Bug 125901 has been marked as a duplicate of this bug. ***