diff --git a/browser/devtools/shared/test/browser.ini b/browser/devtools/shared/test/browser.ini
index 12899fc24159..02dfc15580b1 100644
--- a/browser/devtools/shared/test/browser.ini
+++ b/browser/devtools/shared/test/browser.ini
@@ -66,6 +66,7 @@ support-files =
 [browser_graphs-09f.js]
 [browser_graphs-10a.js]
 [browser_graphs-10b.js]
+[browser_graphs-10c.js]
 [browser_graphs-11a.js]
 [browser_graphs-11b.js]
 [browser_graphs-12.js]
diff --git a/browser/devtools/shared/test/browser_graphs-10c.js b/browser/devtools/shared/test/browser_graphs-10c.js
new file mode 100644
index 000000000000..e802f6c1462e
--- /dev/null
+++ b/browser/devtools/shared/test/browser_graphs-10c.js
@@ -0,0 +1,86 @@
+
+// Tests that graphs properly handle resizing.
+
+const TEST_DATA = [{ delta: 112, value: 48 }, { delta: 213, value: 59 }, { delta: 313, value: 60 }, { delta: 413, value: 59 }, { delta: 530, value: 59 }, { delta: 646, value: 58 }, { delta: 747, value: 60 }, { delta: 863, value: 48 }, { delta: 980, value: 37 }, { delta: 1097, value: 30 }, { delta: 1213, value: 29 }, { delta: 1330, value: 23 }, { delta: 1430, value: 10 }, { delta: 1534, value: 17 }, { delta: 1645, value: 20 }, { delta: 1746, value: 22 }, { delta: 1846, value: 39 }, { delta: 1963, value: 26 }, { delta: 2080, value: 27 }, { delta: 2197, value: 35 }, { delta: 2312, value: 47 }, { delta: 2412, value: 53 }, { delta: 2514, value: 60 }, { delta: 2630, value: 37 }, { delta: 2730, value: 36 }, { delta: 2830, value: 37 }, { delta: 2946, value: 36 }, { delta: 3046, value: 40 }, { delta: 3163, value: 47 }, { delta: 3280, value: 41 }, { delta: 3380, value: 35 }, { delta: 3480, value: 27 }, { delta: 3580, value: 39 }, { delta: 3680, value: 42 }, { delta: 3780, value: 49 }, { delta: 3880, value: 55 }, { delta: 3980, value: 60 }, { delta: 4080, value: 60 }, { delta: 4180, value: 60 }];
+let {LineGraphWidget} = Cu.import("resource:///modules/devtools/Graphs.jsm", {});
+let {Promise} = devtools.require("resource://gre/modules/Promise.jsm");
+
+add_task(function*() {
+  yield promiseTab("about:blank");
+  yield performTest();
+  gBrowser.removeCurrentTab();
+});
+
+function* performTest() {
+  let [host, win, doc] = yield createHost("window");
+  doc.body.setAttribute("style", "position: fixed; width: 100%; height: 100%; margin: 0;");
+
+  let graph = new LineGraphWidget(doc.body, "fps");
+  yield graph.once("ready");
+
+  let refreshCount = 0;
+  graph.on("refresh", () => refreshCount++);
+
+  yield testGraph(host, graph);
+
+  is(refreshCount, 2, "The graph should've been refreshed 2 times.");
+
+  yield graph.destroy();
+  host.destroy();
+}
+
+function* testGraph(host, graph) {
+  graph.setData(TEST_DATA);
+
+  host._window.resizeTo(500, 500);
+  yield graph.once("refresh");
+  let oldBounds = host.frame.getBoundingClientRect();
+
+  is (graph._width, oldBounds.width * window.devicePixelRatio,
+    "The window was properly resized (1).");
+  is (graph._height, oldBounds.height * window.devicePixelRatio,
+    "The window was properly resized (1).");
+
+  dragStart(graph, 100);
+  dragStop(graph, 400);
+
+  is(graph.getSelection().start, 100,
+    "The current selection start value is correct (1).");
+  is(graph.getSelection().end, 400,
+    "The current selection end value is correct (1).");
+
+  info("Making sure the selection updates when the window is resized");
+
+  host._window.resizeTo(250, 250);
+  yield graph.once("refresh");
+  let newBounds = host.frame.getBoundingClientRect();
+
+  is (graph._width, newBounds.width * window.devicePixelRatio,
+    "The window was properly resized (2).");
+  is (graph._height, newBounds.height * window.devicePixelRatio,
+    "The window was properly resized (2).");
+
+  let ratio = oldBounds.width / newBounds.width;
+  info("The window resize ratio is: " + ratio);
+
+  is(graph.getSelection().start, Math.round(100 / ratio),
+    "The current selection start value is correct (2).");
+  is(graph.getSelection().end, Math.round(400 / ratio),
+    "The current selection end value is correct (2).");
+}
+
+// EventUtils just doesn't work!
+
+function dragStart(graph, x, y = 1) {
+  x /= window.devicePixelRatio;
+  y /= window.devicePixelRatio;
+  graph._onMouseMove({ testX: x, testY: y });
+  graph._onMouseDown({ testX: x, testY: y });
+}
+
+function dragStop(graph, x, y = 1) {
+  x /= window.devicePixelRatio;
+  y /= window.devicePixelRatio;
+  graph._onMouseMove({ testX: x, testY: y });
+  graph._onMouseUp({ testX: x, testY: y });
+}
diff --git a/browser/devtools/shared/widgets/Graphs.jsm b/browser/devtools/shared/widgets/Graphs.jsm
index b109a4917095..4be2bcf28ccc 100644
--- a/browser/devtools/shared/widgets/Graphs.jsm
+++ b/browser/devtools/shared/widgets/Graphs.jsm
@@ -684,6 +684,13 @@ AbstractCanvasGraph.prototype = {
       return;
     }
 
+    // Handle a changed size by mapping the old selection to the new width
+    if (this._width && newWidth && this.hasSelection()) {
+      let ratio = this._width / (newWidth * this._pixelRatio);
+      this._selection.start = Math.round(this._selection.start / ratio);
+      this._selection.end = Math.round(this._selection.end / ratio);
+    }
+
     bounds.width = newWidth;
     bounds.height = newHeight;
     this._iframe.setAttribute("width", bounds.width);