Add GUI option to switch off showing the document title

Pleasing users is not so bad
BUGS: 158401

conf/dlggeneralbase.ui

@@ -58,6 +58,13 @@
           </property>
          </widget>
         </item>
+        <item>
+         <widget class="QCheckBox" name="kcfg_DisplayDocumentTitle">
+          <property name="text">
+           <string>Display document title in title bar</string>
+          </property>
+         </widget>
+        </item>
        </layout>
       </item>
       <item>

part.cpp

@@ -1738,6 +1738,8 @@ void Part::slotNewConfig()
     // update Reviews settings
     if ( m_sidebar->isItemEnabled(2) )
         m_reviewsWidget->reparseConfig();
+
+    setWindowTitleFromDocument ();
 }