Ticket #6467: 6467.patch

_source/plugins/maximize/plugin.js

@@ -333 +333 @@
                                         command : 'maximize'
                                 } );
 
-                        // Restore the command state after mode change.
+                        // Restore the command state after mode change, unless it has been changed to disabled (#6467)
                         editor.on( 'mode', function()
                                 {
-                                        editor.getCommand( 'maximize' ).setState( savedState );
+                                        var command = editor.getCommand( 'maximize' );
+                                        command.setState( command.state == CKEDITOR.TRISTATE_DISABLED ? CKEDITOR.TRISTATE_DISABLED : savedState );
                                 }, null, null, 100 );
                 }
         } );