diff --git a/polygerrit-ui/app/elements/diff/gr-diff-cursor/gr-diff-cursor.js b/polygerrit-ui/app/elements/diff/gr-diff-cursor/gr-diff-cursor.js
index e3a4821..a18d2f4 100644
--- a/polygerrit-ui/app/elements/diff/gr-diff-cursor/gr-diff-cursor.js
+++ b/polygerrit-ui/app/elements/diff/gr-diff-cursor/gr-diff-cursor.js
@@ -194,9 +194,13 @@
     },
 
     getTargetDiffElement() {
-      // Find the parent diff element of the cursor row.
-      for (let diff = this.diffRow; diff; diff = diff.parentElement) {
-        if (diff.tagName === 'GR-DIFF') { return diff; }
+      if (!this.diffRow) return null;
+
+      const hostOwner = Polymer.dom(/** @type {Node} */ (this.diffRow))
+        .getOwnerRoot();
+      if (hostOwner && hostOwner.host &&
+          hostOwner.host.tagName === 'GR-DIFF') {
+        return hostOwner.host;
       }
       return null;
     },
diff --git a/polygerrit-ui/app/elements/diff/gr-diff-cursor/gr-diff-cursor_test.html b/polygerrit-ui/app/elements/diff/gr-diff-cursor/gr-diff-cursor_test.html
index 7280f2f..ffb5efa 100644
--- a/polygerrit-ui/app/elements/diff/gr-diff-cursor/gr-diff-cursor_test.html
+++ b/polygerrit-ui/app/elements/diff/gr-diff-cursor/gr-diff-cursor_test.html
@@ -249,6 +249,15 @@
       diffElement._diffChanged(mockDiffResponse.diffResponse);
     });
 
+    test('getTargetDiffElement', () => {
+      cursorElement.initialLineNumber = 1;
+      assert.isTrue(!!cursorElement.diffRow);
+      assert.equal(
+          cursorElement.getTargetDiffElement(),
+          diffElement
+      );
+    });
+
     test('getAddress', () => {
       // It should initialize to the first chunk: line 5 of the revision.
       assert.deepEqual(cursorElement.getAddress(),