speedup transition adn use class instead of id

IPython/frontend/html/notebook/static/less/notebook.less

@@ -87,7 +87,7 @@ span#notebook_name {
     border-bottom: @borderwidth @border_color solid;
 }
 
-.toolbar select, #maintoolbar label {
+.toolbar select, .toolbar label {
     height : 23px;
     vertical-align: top;
     margin-right:2px;

IPython/frontend/html/notebook/static/less/tooltip.less

@@ -30,13 +30,13 @@
 }
 
 // smoth height adaptation
-.smoothheight(@t:1s) {
+.smoothheight(@t:500ms) {
     -webkit-transition-property: height;
-    -webkit-transition-duration: 1s;
+    -webkit-transition-duration: @t;
     -moz-transition-property: height;
-    -moz-transition-duration: 1s;
+    -moz-transition-duration: @t;
     transition-property: height;
-    transition-duration: 1s;
+    transition-duration: @t;
 }
 
 @-moz-keyframes fadeOut {