Ticket #6375: 6375_2.patch

_source/plugins/selection/plugin.js

@@ -174 +174 @@
                                                 {
                                                         editor.on( 'blur', function( evt )
                                                         {
-                                                                editor.document && editor.document.$.selection.empty();
+                                                                // Try/Catch to avoid errors if the editor is hidden. (#6375)
+                                                                try
+                                                                {
+                                                                        editor.document && editor.document.$.selection.empty();
+                                                                }
+                                                                catch (e) {}
                                                         });
                                                 }