Improve special key handling in completer

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

@@ -255,6 +255,15 var IPython = (function (IPython) {
     Completer.prototype.keydown = function (event) {
         var code = event.keyCode;
         var that = this;
+        var special_key = false;
+        
+        // detect special keys like SHIFT,PGUP,...
+        for( var _key in key ) {
+            if (code == key[_key] ) {
+                special_key = true;
+            }
+        };         
+
         // Enter
         if (code == key.ENTER) {
             CodeMirror.e_stop(event);
@@ -288,7 +297,7 var IPython = (function (IPython) {
             // need to do that to be able to move the arrow
             // when on the first or last line ofo a code cell
             event.stopPropagation();
-        } else if (code != key.UPARROW && code != key.DOWNARROW) {
+        } else if (special_key != true) { 
             this.close();
             this.editor.focus();
             //we give focus to the editor immediately and call sell in 50 ms