diff --git a/polygerrit-ui/app/elements/diff/gr-diff/gr-diff.js b/polygerrit-ui/app/elements/diff/gr-diff/gr-diff.js
index edb676effd..ba5138fc5a 100644
--- a/polygerrit-ui/app/elements/diff/gr-diff/gr-diff.js
+++ b/polygerrit-ui/app/elements/diff/gr-diff/gr-diff.js
@@ -908,7 +908,8 @@
           !chunk.ab &&
 
           // The chunk doesn't have the given side.
-          ((leftSide && !chunk.a) || (!leftSide && !chunk.b)));
+          ((leftSide && (!chunk.a || !chunk.a.length)) ||
+           (!leftSide && (!chunk.b || !chunk.b.length))));
 
       // If we reached the beginning of the diff and failed to find a chunk
       // with the given side, return null.
diff --git a/polygerrit-ui/app/elements/diff/gr-diff/gr-diff_test.html b/polygerrit-ui/app/elements/diff/gr-diff/gr-diff_test.html
index 5366664f6a..082a03220f 100644
--- a/polygerrit-ui/app/elements/diff/gr-diff/gr-diff_test.html
+++ b/polygerrit-ui/app/elements/diff/gr-diff/gr-diff_test.html
@@ -851,7 +851,7 @@ limitations under the License.
           assert.equal(element._lastChunkForSide(diff, true), diff.content[3]);
         });
 
-        test('addition', () => {
+        test('addition with a undefined', () => {
           const diff = {content: [
             {b: ['foo', 'bar', 'baz']},
           ]};
@@ -859,7 +859,16 @@ limitations under the License.
           assert.isNull(element._lastChunkForSide(diff, true));
         });
 
-        test('deletion', () => {
+        test('addition with a empty', () => {
+          const diff = {content: [
+            {a: [], b: ['foo', 'bar', 'baz']},
+          ]};
+          assert.equal(element._lastChunkForSide(diff, false), diff.content[0]);
+          assert.isNull(element._lastChunkForSide(diff, true));
+        });
+
+
+        test('deletion with b undefined', () => {
           const diff = {content: [
             {a: ['foo', 'bar', 'baz']},
           ]};
@@ -867,6 +876,14 @@ limitations under the License.
           assert.equal(element._lastChunkForSide(diff, true), diff.content[0]);
         });
 
+        test('deletion with b empty', () => {
+          const diff = {content: [
+            {a: ['foo', 'bar', 'baz'], b: []},
+          ]};
+          assert.isNull(element._lastChunkForSide(diff, false));
+          assert.equal(element._lastChunkForSide(diff, true), diff.content[0]);
+        });
+
         test('empty', () => {
           const diff = {content: []};
           assert.isNull(element._lastChunkForSide(diff, false));