diff --git a/package.json b/package.json
index d6902c5dd..02caa814e 100644
--- a/package.json
+++ b/package.json
@@ -60,7 +60,7 @@
     "stats.js": "^0.17.0",
     "tap": "^10.2.0",
     "tiny-worker": "^2.1.1",
-    "webpack": "^2.4.1",
+    "webpack": "^3.10.0",
     "webpack-dev-server": "^2.4.1",
     "worker-loader": "1.1.0"
   }
diff --git a/src/engine/runtime.js b/src/engine/runtime.js
index c425fa334..bf7969a0c 100644
--- a/src/engine/runtime.js
+++ b/src/engine/runtime.js
@@ -618,16 +618,20 @@ class Runtime extends EventEmitter {
 
         blockJSON.message0 = '';
 
-        // If an icon for the extension exists, prepend it to each block
+        // If an icon for the extension exists, prepend it to each block, with a vertical separator.
         if (categoryInfo.blockIconURI) {
-            blockJSON.message0 = '%1';
+            blockJSON.message0 = '%1 %2';
             const iconJSON = {
                 type: 'field_image',
                 src: categoryInfo.blockIconURI,
                 width: 40,
                 height: 40
             };
+            const separatorJSON = {
+                type: 'field_vertical_separator'
+            };
             blockJSON.args0.push(iconJSON);
+            blockJSON.args0.push(separatorJSON);
         }
 
         blockJSON.message0 += blockInfo.text.replace(/\[(.+?)]/g, (match, placeholder) => {