minor adjustments to sidebar, adding mock-ups.

css/app.css

@@ -643,6 +643,7 @@ a:hover .icon.out-link   { background-position: -500px -14px;}
     height: 100%;
     overflow: hidden;
     z-index: 2;
+    background: #f6f6f6;
 }
 
 .inspector-wrap {

js/id/ui.js

@@ -15,7 +15,7 @@ iD.ui = function(context) {
 
         container.append('div')
             .attr('id', 'sidebar')
-            .attr('class', 'col4 fillL2')
+            .attr('class', 'col4')
             .call(iD.ui.Sidebar(context));
 
         var m = container.append('div')