commit 7d810146ed97b38a986d3b9d19870e4d839439cd
Author: Jason Laster <jason.laster.11@gmail.com>
Date:   Mon Aug 20 16:54:00 2018 -0400

    ...

diff --git a/assets/images/Svg.js b/assets/images/Svg.js
index de1c776..51cc8ad 100644
--- a/assets/images/Svg.js
+++ b/assets/images/Svg.js
@@ -26,6 +26,7 @@ const svg = {
   folder: require("./folder.svg"),
   globe: require("./globe.svg"),
   home: require("./home.svg"),
+  information: require("./information.svg"),
   javascript: require("./javascript.svg"),
   jquery: require("./jquery.svg"),
   underscore: require("./underscore.svg"),
diff --git a/src/components/SecondaryPanes/Scopes.js b/src/components/SecondaryPanes/Scopes.js
index fa83f61..6cc737b 100644
--- a/src/components/SecondaryPanes/Scopes.js
+++ b/src/components/SecondaryPanes/Scopes.js
@@ -22,6 +22,7 @@ import { ObjectInspector } from "devtools-reps";
 import type { Pause, Why } from "../../types";
 import type { NamedValue } from "../../utils/pause/scopes/types";

+import Svg from "../shared/Svg";
 import "./Scopes.css";

 type Props = {
@@ -126,6 +127,19 @@ class Scopes extends PureComponent<Props, State> {
                   : L10N.getStr("scopes.toggleToOriginal")}
               </a>
             </div>
+
+            <div className="scope-type-toggle">
+              <a
+                href=""
+                onClick={e => {
+                  e.preventDefault();
+                  this.setState({ showOriginal: !showOriginal });
+                }}
+              >
+                <Svg name="information" title="..." aria-label="..." />
+                Source Maps
+              </a>
+            </div>
           ) : null}
         </div>
       );
diff --git a/src/components/shared/Svg.css b/src/components/shared/Svg.css
index 15d2801..d8bce15 100644
--- a/src/components/shared/Svg.css
+++ b/src/components/shared/Svg.css
@@ -37,7 +37,8 @@
 .worker svg,
 .refresh svg,
 .shortcut svg,
-.add-button svg {
+.add-button svg,
+.information svg {
   width: 15px;
 }

diff --git a/src/reducers/pause.js b/src/reducers/pause.js
index 502ab39..3f748b1 100644
--- a/src/reducers/pause.js
+++ b/src/reducers/pause.js
@@ -54,7 +54,8 @@ export type PauseState = {
       [FrameId]: {
         [string]: string | null
       }
-    }
+    },
+    mappingsType: "column" | "line" | null
   },
   selectedFrameId: ?string,
   selectedComponentIndex: ?number,
@@ -86,7 +87,8 @@ const emptyPauseState = {
   frameScopes: {
     generated: {},
     original: {},
-    mappings: {}
+    mappings: {},
+    mappingsType: null
   },
   selectedFrameId: null,
   loadedObjects: {},
@@ -168,12 +170,14 @@ function update(
         ...state.frameScopes.mappings,
         [selectedFrameId]: value && value.mappings
       };
+
       return {
         ...state,
         frameScopes: {
           ...state.frameScopes,
           original,
-          mappings
+          mappings,
+          mappingsType: "column"
         }
       };
     }
diff --git a/src/utils/pause/mapScopes/index.js b/src/utils/pause/mapScopes/index.js
index 1f6fa97..158f4c0 100644
--- a/src/utils/pause/mapScopes/index.js
+++ b/src/utils/pause/mapScopes/index.js
@@ -73,7 +73,7 @@ export async function buildMappedScopes(
   );

   if (originalRanges.every(range => range.columnEnd === Infinity)) {
-    return null;
+    return { mappingsType: "line" };
   }

   const generatedAstBindings = buildGeneratedBindingList(