diff -r 000000000000 -r 6474c204b198 browser/devtools/debugger/test/browser_dbg_blackboxing-06.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/browser/devtools/debugger/test/browser_dbg_blackboxing-06.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,57 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+/**
+ * Test that clicking the black box checkbox when paused doesn't re-select the
+ * currently paused frame's source.
+ */
+
+const TAB_URL = EXAMPLE_URL + "doc_blackboxing.html";
+
+let gTab, gDebuggee, gPanel, gDebugger;
+let gSources;
+
+function test() {
+  initDebugger(TAB_URL).then(([aTab, aDebuggee, aPanel]) => {
+    gTab = aTab;
+    gDebuggee = aDebuggee;
+    gPanel = aPanel;
+    gDebugger = gPanel.panelWin;
+    gSources = gDebugger.DebuggerView.Sources;
+
+    waitForSourceAndCaretAndScopes(gPanel, ".html", 21)
+      .then(testBlackBox)
+      .then(() => resumeDebuggerThenCloseAndFinish(gPanel))
+      .then(null, aError => {
+        ok(false, "Got an error: " + aError.message + "\n" + aError.stack);
+      });
+
+    gDebuggee.runTest();
+  });
+}
+
+function testBlackBox() {
+  const selectedUrl = gSources.selectedValue;
+
+  let finished = waitForSourceShown(gPanel, "blackboxme.js").then(() => {
+    const newSelectedUrl = gSources.selectedValue;
+    isnot(selectedUrl, newSelectedUrl,
+      "Should not have the same url selected.");
+
+    return toggleBlackBoxing(gPanel).then(() => {
+      is(gSources.selectedValue, newSelectedUrl,
+        "The selected source did not change.");
+    });
+  });
+
+  gSources.selectedIndex = 0;
+  return finished;
+}
+
+registerCleanupFunction(function() {
+  gTab = null;
+  gDebuggee = null;
+  gPanel = null;
+  gDebugger = null;
+  gSources = null;
+});