Make focus follow shift-selection.

notebook/static/notebook/js/actions.js

@@ -183,14 +183,22 @@ define(function(require){
             help: 'extend selected cells above',
             help_index : 'dc',
             handler : function (env) {
-                env.notebook.extend_selection_by(-1)
+                env.notebook.extend_selection_by(-1);
+                // scroll into view, 
+                // do not call notebook.focus_cell(), or 
+                // all the selection get thrown away
+                env.notebook.get_selected_cell().element.focus();
             }
         },
         'extend-selection-below' : {
             help: 'extend selected cells below',
             help_index : 'dd',
             handler : function (env) {
-                env.notebook.extend_selection_by(1)
+                env.notebook.extend_selection_by(1);
+                // scroll into view, 
+                // do not call notebook.focus_cell(), or 
+                // all the selection get thrown away
+                env.notebook.get_selected_cell().element.focus();
             }
         },
         'cut-cell' : {

notebook/static/notebook/js/notebook.js

@@ -607,7 +607,7 @@ define(function (require) {
      * @return {Cell} The selected cell
      */
     Notebook.prototype.get_selected_cell = function () {
-        var index = this.get_selected_cells_indices();
+        var index = this.get_selected_index();
         return this.get_cell(index);
     };
 
@@ -711,7 +711,7 @@ define(function (require) {
                 this.get_cell(sindex).unselect(moveanchor);
             }
             if(moveanchor){
-                this.get_cell(this.get_anchor_index()).unselect(true);
+                this.get_cell(this.get_anchor_index()).unselect(moveanchor);
             }
             var cell = this.get_cell(index);
             cell.select(moveanchor);