for downloads, replaced window.open with window.location.assign

This doesn't actually open a new windows, so it's a bit nicer. 
Not very important, though.
Source: [StackOverflow](http://stackoverflow.com/questions/1066452/easiest-way-to-open-a-download-window-without-navigating-away-from-the-page)

IPython/frontend/html/notebook/static/js/menubar.js

@@ -1,198 +1,198
 //----------------------------------------------------------------------------
 //  Copyright (C) 2008-2011  The IPython Development Team
 //
 //  Distributed under the terms of the BSD License.  The full license is in
 //  the file COPYING, distributed as part of this software.
 //----------------------------------------------------------------------------
 
 //============================================================================
 // MenuBar
 //============================================================================
 
 var IPython = (function (IPython) {
 
     var MenuBar = function (selector) {
         this.selector = selector;
         if (this.selector !== undefined) {
             this.element = $(selector);
             this.style();
             this.bind_events();
         }
     };
 
 
     MenuBar.prototype.style = function () {
         this.element.addClass('border-box-sizing');
         $('ul#menus').menubar({
             select : function (event, ui) {
                 // The selected cell loses focus when the menu is entered, so we
                 // re-select it upon selection.
                 var i = IPython.notebook.get_selected_index();
                 IPython.notebook.select(i);
             }
         });
     };
 
 
     MenuBar.prototype.bind_events = function () {
         //  File
         this.element.find('#new_notebook').click(function () {
             window.open($('body').data('baseProjectUrl')+'new');
         });
         this.element.find('#open_notebook').click(function () {
             window.open($('body').data('baseProjectUrl'));
         });
         this.element.find('#rename_notebook').click(function () {
             IPython.save_widget.rename_notebook();
         });
         this.element.find('#copy_notebook').click(function () {
             var notebook_id = IPython.notebook.get_notebook_id();
             var url = $('body').data('baseProjectUrl') + notebook_id + '/copy';
             window.open(url,'_blank');
             return false;
         });
         this.element.find('#save_notebook').click(function () {
             IPython.notebook.save_notebook();
         });
         this.element.find('#download_ipynb').click(function () {
             var notebook_id = IPython.notebook.get_notebook_id();
             var url = $('body').data('baseProjectUrl') + 'notebooks/' +
                       notebook_id + '?format=json';
-            window.open(url,'_newtab');
+            window.location.assign(url);
         });
         this.element.find('#download_py').click(function () {
             var notebook_id = IPython.notebook.get_notebook_id();
             var url = $('body').data('baseProjectUrl') + 'notebooks/' +
                       notebook_id + '?format=py';
-            window.open(url,'_newtab');
+            window.location.assign(url);
         });
         this.element.find('button#print_notebook').click(function () {
             IPython.print_widget.print_notebook();
         });
         this.element.find('#kill_and_exit').click(function () {
             IPython.notebook.kernel.kill();
             setTimeout(function(){window.close();}, 200);
         });
         // Edit
         this.element.find('#cut_cell').click(function () {
             IPython.notebook.cut_cell();
         });
         this.element.find('#copy_cell').click(function () {
             IPython.notebook.copy_cell();
         });
         this.element.find('#delete_cell').click(function () {
             IPython.notebook.delete_cell();
         });
         this.element.find('#split_cell').click(function () {
             IPython.notebook.split_cell();
         });
         this.element.find('#merge_cell_above').click(function () {
             IPython.notebook.merge_cell_above();
         });
         this.element.find('#merge_cell_below').click(function () {
             IPython.notebook.merge_cell_below();
         });
         this.element.find('#move_cell_up').click(function () {
             IPython.notebook.move_cell_up();
         });
         this.element.find('#move_cell_down').click(function () {
             IPython.notebook.move_cell_down();
         });
         this.element.find('#select_previous').click(function () {
             IPython.notebook.select_prev();
         });
         this.element.find('#select_next').click(function () {
             IPython.notebook.select_next();
         });
         // View
         this.element.find('#toggle_header').click(function () {
             $('div#header').toggle();
             IPython.layout_manager.do_resize();
         });
         this.element.find('#toggle_toolbar').click(function () {
             IPython.toolbar.toggle();
         });
         // Insert
         this.element.find('#insert_cell_above').click(function () {
             IPython.notebook.insert_cell_above('code');
         });
         this.element.find('#insert_cell_below').click(function () {
             IPython.notebook.insert_cell_below('code');
         });
         // Cell
         this.element.find('#run_cell').click(function () {
             IPython.notebook.execute_selected_cell();
         });
         this.element.find('#run_cell_in_place').click(function () {
             IPython.notebook.execute_selected_cell({terminal:true});
         });
         this.element.find('#run_all_cells').click(function () {
             IPython.notebook.execute_all_cells();
         }).attr('title', 'Run all cells in the notebook');
         this.element.find('#run_all_cells_above').click(function () {
             IPython.notebook.execute_cells_above();
         }).attr('title', 'Run all cells above (but not including) this cell');
         this.element.find('#run_all_cells_below').click(function () {
             IPython.notebook.execute_cells_below();
         }).attr('title', 'Run this cell and all cells below it');
         this.element.find('#to_code').click(function () {
             IPython.notebook.to_code();
         });
         this.element.find('#to_markdown').click(function () {
             IPython.notebook.to_markdown();
         });
         this.element.find('#to_raw').click(function () {
             IPython.notebook.to_raw();
         });
         this.element.find('#to_heading1').click(function () {
             IPython.notebook.to_heading(undefined, 1);
         });
         this.element.find('#to_heading2').click(function () {
             IPython.notebook.to_heading(undefined, 2);
         });
         this.element.find('#to_heading3').click(function () {
             IPython.notebook.to_heading(undefined, 3);
         });
         this.element.find('#to_heading4').click(function () {
             IPython.notebook.to_heading(undefined, 4);
         });
         this.element.find('#to_heading5').click(function () {
             IPython.notebook.to_heading(undefined, 5);
         });
         this.element.find('#to_heading6').click(function () {
             IPython.notebook.to_heading(undefined, 6);
         });
         this.element.find('#toggle_output').click(function () {
             IPython.notebook.toggle_output();
         });
         this.element.find('#collapse_all_output').click(function () {
             IPython.notebook.collapse_all_output();
         });
         this.element.find('#scroll_all_output').click(function () {
             IPython.notebook.scroll_all_output();
         });
         this.element.find('#expand_all_output').click(function () {
             IPython.notebook.expand_all_output();
         });
         this.element.find('#clear_all_output').click(function () {
             IPython.notebook.clear_all_output();
         });
         // Kernel
         this.element.find('#int_kernel').click(function () {
             IPython.notebook.kernel.interrupt();
         });
         this.element.find('#restart_kernel').click(function () {
             IPython.notebook.restart_kernel();
         });
         // Help
         this.element.find('#keyboard_shortcuts').click(function () {
             IPython.quick_help.show_keyboard_shortcuts();
         });
     };
 
 
     IPython.MenuBar = MenuBar;
 
     return IPython;
 
 }(IPython));