use one-off notification widget for match notification

when no exact match, and only one kernel matches language

IPython/html/static/notebook/js/kernelselector.js

@@ -201,6 +201,12 b' define(['
             }
             if (matches.length === 1) {
                 ks = kernelspecs[matches[0]];
+                console.log("No exact match found for " + selected.name +
+                    ", using only kernel that matches language=" + selected.language, ks);
+                this.events.trigger("spec_match_found.Kernel", {
+                    selected: selected,
+                    found: ks,
+                });
             }
             // if still undefined, trigger failure event
             if (ks === undefined) {

IPython/html/static/notebook/js/notificationarea.js

@@ -14,7 +14,7 b' define(['
         this.save_widget = options.save_widget;
         this.notebook = options.notebook;
         this.keyboard_manager = options.keyboard_manager;
-    }
+    };
     
     NotebookNotificationArea.prototype = Object.create(NotificationArea.prototype);
     
@@ -38,7 +38,7 b' define(['
         var knw = this.new_notification_widget('kernel');
         var $kernel_ind_icon = $("#kernel_indicator_icon");
         var $modal_ind_icon = $("#modal_indicator");
-        var $body = $('body')
+        var $body = $('body');
 
         // Command/Edit mode
         this.events.on('edit_mode.Notebook', function () {
@@ -57,9 +57,9 b' define(['
 
         // Implicitly start off in Command mode, switching to Edit mode will trigger event
         $modal_ind_icon.addClass('modal_indicator').attr('title','Command Mode');
-        $body.addClass('command_mode')
+        $body.addClass('command_mode');
 
-        // Kernel events 
+        // Kernel events
 
         // this can be either kernel_created.Kernel or kernel_created.Session
         this.events.on('kernel_created.Kernel kernel_created.Session', function () {
@@ -105,7 +105,7 b' define(['
                         }
                     }
                 });
-            };
+            }
 
             that.save_widget.update_document_title();
             knw.danger("Dead kernel");
@@ -255,6 +255,13 b' define(['
             window.document.title='(Busy) '+window.document.title;
             $kernel_ind_icon.attr('class','kernel_busy_icon').attr('title','Kernel Busy');
         });
+
+        this.events.on('spec_match_found.Kernel', function (evt, data) {
+            that.widget('kernelspec').info("Using kernel: " + data.found.spec.display_name, 3000, undefined, {
+                title: "Only candidate for language: " + data.selected.language + " was " + data.found.spec.display_name
+            });
+        });
+
         
         // Start the kernel indicator in the busy state, and send a kernel_info request.
         // When the kernel_info reply arrives, the kernel is idle.