Fix split pane ordering

Author: Ives van Hoorne

src/app/pages/Sandbox/Editor/Content/Header/ShareView.js

@@ -20,7 +20,7 @@ import {
 
 const Container = styled.div`
   position: relative;
-  z-index: 2;
+  z-index: 200;
   height: 100%;
 `;
 

src/app/split-pane.css

@@ -4,7 +4,7 @@
     box-sizing: border-box;
     background: #000;
     opacity: .4;
-    z-index: 50;
+    z-index: 30;
     -moz-background-clip: padding;
     -webkit-background-clip: padding;
     background-clip: padding-box;