Merge pull request #1856 from mcelrath/master

Fix 1px jumping of cells and menus in Notebook as selection moves around, by careful creation of 1px outlines.

IPython/frontend/html/notebook/static/css/notebook.css

@@ -35,6 +35,7 @@ span#notebook_name {
 }
 
 .ui-menu .ui-menu-item a {
+    border: 1px solid transparent;
     padding: 2px 1.6em;
 }
 
@@ -113,6 +114,15 @@ div#pager {
     display: none;
 }
 
+div.ui-widget-content {
+    border: 1px solid #aaa;
+    outline: none;
+}
+
+.cell {
+    border: 1px solid transparent;
+}
+
 div.cell {
     width: 100%;
     padding: 5px 5px 5px 0px;