Following the steps given above I get a dialog which says "Please specify the
filename to save to." which sounds reasonable.

Could this be a bug in the polish translation?

My mistake, sort of, choose the uncompressed XML OASIS format and then do not
enter any filename.

Ah, now I see. :-) The same happens with kspread. So I'm moving this bug to
product koffice.

Bug 56834 seems related.

Confirming with KOffice 1.5.2.

SVN commit 625258 by dfaure:

Revert KoDirectoryStore change, and do url adjustment (when saving as uncompressed) in komainwindow instead, to avoid the "already exists" dialog
BUG: 130980


 M  +14 -0     kofficecore/KoMainWindow.cpp  
 M  +3 -13     store/KoDirectoryStore.cpp  


--- branches/koffice/1.6/koffice/lib/kofficecore/KoMainWindow.cpp #625257:625258
@@ -32,6 +32,7 @@
 #include "kkbdaccessextensions.h"
 #include "KoSpeaker.h"
 
+#include <kaboutdata.h>
 #include <kprinter.h>
 #include <kdeversion.h>
 #include <kstdaction.h>
@@ -836,6 +837,14 @@
                 break;
             }
 
+            // adjust URL before doing checks on whether the file exists.
+            if ( specialOutputFlag == KoDocument::SaveAsDirectoryStore ) {
+                QString fileName = newURL.fileName();
+                if ( fileName != "content.xml"  ) {
+                    newURL.addPath( "content.xml" );
+                }
+            }
+
             // this file exists and we are not just clicking "Save As" to change filter options
             // => ask for confirmation
             if ( KIO::NetAccess::exists( newURL, false /*will write*/, this ) && !justChangingFilterOptions )
@@ -1200,6 +1209,11 @@
 
     if ( title.isEmpty() )
         title = fileName;
+    if ( title.isEmpty() ) {
+        // #139905 - breaks message freeze though
+        //const QString programName = instance()->aboutData() ? instance()->aboutData()->programName() : instance()->instanceName();
+        //title = i18n("%1 unsaved document (%2)").arg(programName).arg(KGlobal::locale()->formatDate(QDate::currentDate(), true/*short*/));
+    }
     printer.setDocName( title );
     printer.setDocFileName( fileName );
     printer.setDocDirectory( rootView()->koDocument()->url().directory() );
--- branches/koffice/1.6/koffice/lib/store/KoDirectoryStore.cpp #625257:625258
@@ -28,19 +28,9 @@
     : m_basePath( path )
 {
     const int pos = path.findRev( '/' );
-    bool stripFileName = false;
-    if (_mode == Read) { // the user clicked on foo/content.xml -> remove filename
-        stripFileName = true;
-    } else {
-        const QString fileName = path.mid(pos+1);
-        stripFileName = fileName == "content.xml";
-    }
-
-    if (stripFileName) {
-        // The parameter must include "maindoc.xml" or "content.xml"
-        if ( pos != -1 && pos != (int)m_basePath.length()-1 )
-            m_basePath = m_basePath.left( pos );
-    }
+    // The parameter must include "maindoc.xml" or "content.xml"
+    if ( pos != -1 && pos != (int)m_basePath.length()-1 )
+        m_basePath = m_basePath.left( pos );
     if ( !m_basePath.endsWith("/") )
         m_basePath += '/';
     m_currentPath = m_basePath;