diff --git a/scm-ui/ui-components/src/repos/DiffExpander.test.ts b/scm-ui/ui-components/src/repos/DiffExpander.test.ts
index d01de8fd09..d7d0bde027 100644
--- a/scm-ui/ui-components/src/repos/DiffExpander.test.ts
+++ b/scm-ui/ui-components/src/repos/DiffExpander.test.ts
@@ -204,8 +204,8 @@ describe("with hunks the diff expander", () => {
   it("should expand hunk with new line from api client at the bottom", async () => {
     expect(diffExpander.getHunk(1).hunk.changes.length).toBe(7);
     fetchMock.get(
-      "http://localhost:8081/scm/api/v2/content/abc/CommitMessage.js?start=22&end=22",
-      "new line 1\nnew line 2"
+      "http://localhost:8081/scm/api/v2/content/abc/CommitMessage.js?start=20&end=21",
+      "new line 1"
     );
     let newFile;
     diffExpander.getHunk(1).expandBottom(file => {
@@ -213,15 +213,14 @@ describe("with hunks the diff expander", () => {
     });
     await fetchMock.flush(true);
     expect(fetchMock.done()).toBe(true);
-    expect(newFile.hunks[1].changes.length).toBe(9);
+    expect(newFile.hunks[1].changes.length).toBe(8);
     expect(newFile.hunks[1].changes[7].content).toBe("new line 1");
-    expect(newFile.hunks[1].changes[8].content).toBe("new line 2");
   });
   it("should expand hunk with new line from api client at the top", async () => {
     expect(diffExpander.getHunk(1).hunk.changes.length).toBe(7);
     fetchMock.get(
-      "http://localhost:8081/scm/api/v2/content/abc/CommitMessage.js?start=9&end=13",
-      "new line 1\nnew line 2"
+      "http://localhost:8081/scm/api/v2/content/abc/CommitMessage.js?start=8&end=13",
+      "new line 9\nnew line 10\nnew line 11\nnew line 12\nnew line 13"
     );
     let newFile;
     diffExpander.getHunk(1).expandHead(file => {
@@ -229,13 +228,19 @@ describe("with hunks the diff expander", () => {
     });
     await fetchMock.flush(true);
     expect(fetchMock.done()).toBe(true);
-    expect(newFile.hunks[1].changes.length).toBe(9);
-    expect(newFile.hunks[1].changes[0].content).toBe("new line 1");
-    expect(newFile.hunks[1].changes[0].oldLineNumber).toBe(12);
-    expect(newFile.hunks[1].changes[0].newLineNumber).toBe(12);
-    expect(newFile.hunks[1].changes[1].content).toBe("new line 2");
-    expect(newFile.hunks[1].changes[1].oldLineNumber).toBe(13);
-    expect(newFile.hunks[1].changes[1].newLineNumber).toBe(13);
+    expect(newFile.hunks[1].changes.length).toBe(12);
+    expect(newFile.hunks[1].changes[0].content).toBe("new line 9");
+    expect(newFile.hunks[1].changes[0].oldLineNumber).toBe(9);
+    expect(newFile.hunks[1].changes[0].newLineNumber).toBe(9);
+    expect(newFile.hunks[1].changes[1].content).toBe("new line 10");
+    expect(newFile.hunks[1].changes[1].oldLineNumber).toBe(10);
+    expect(newFile.hunks[1].changes[1].newLineNumber).toBe(10);
+    expect(newFile.hunks[1].changes[4].content).toBe("new line 13");
+    expect(newFile.hunks[1].changes[4].oldLineNumber).toBe(13);
+    expect(newFile.hunks[1].changes[4].newLineNumber).toBe(13);
+    expect(newFile.hunks[1].changes[5].content).toBe("line");
+    expect(newFile.hunks[1].changes[5].oldLineNumber).toBe(14);
+    expect(newFile.hunks[1].changes[5].newLineNumber).toBe(14);
   });
 });
 
diff --git a/scm-ui/ui-components/src/repos/DiffExpander.ts b/scm-ui/ui-components/src/repos/DiffExpander.ts
index cac5818de4..0311636d7c 100644
--- a/scm-ui/ui-components/src/repos/DiffExpander.ts
+++ b/scm-ui/ui-components/src/repos/DiffExpander.ts
@@ -45,7 +45,7 @@ class DiffExpander {
   };
 
   maxLineNumber: (n: number) => number = (n: number) => {
-    return this.file.hunks![n]!.newStart! + this.file.hunks![n]!.newLines!;
+    return this.file.hunks![n]!.newStart! + this.file.hunks![n]!.newLines! - 1;
   };
 
   computeMaxExpandHeadRange = (n: number) => {
@@ -54,7 +54,7 @@ class DiffExpander {
     } else if (n === 0) {
       return this.minLineNumber(n) - 1;
     }
-    return this.minLineNumber(n) - this.maxLineNumber(n - 1);
+    return this.minLineNumber(n) - this.maxLineNumber(n - 1) - 1;
   };
 
   computeMaxExpandBottomRange = (n: number) => {
@@ -63,12 +63,12 @@ class DiffExpander {
     } else if (n === this.file!.hunks!.length - 1) {
       return Number.MAX_SAFE_INTEGER;
     }
-    return this.minLineNumber(n + 1) - this.maxLineNumber(n);
+    return this.minLineNumber(n + 1) - this.maxLineNumber(n) - 1;
   };
 
   expandHead = (n: number, callback: (newFile: File) => void) => {
     const lineRequestUrl = this.file._links.lines.href
-      .replace("{start}", this.minLineNumber(n) - Math.min(10, this.computeMaxExpandHeadRange(n)))
+      .replace("{start}", this.minLineNumber(n) - Math.min(10, this.computeMaxExpandHeadRange(n)) - 1)
       .replace("{end}", this.minLineNumber(n) - 1);
     apiClient
       .get(lineRequestUrl)
@@ -79,7 +79,7 @@ class DiffExpander {
 
   expandBottom = (n: number, callback: (newFile: File) => void) => {
     const lineRequestUrl = this.file._links.lines.href
-      .replace("{start}", this.maxLineNumber(n) + 1)
+      .replace("{start}", this.maxLineNumber(n))
       .replace("{end}", this.maxLineNumber(n) + Math.min(10, this.computeMaxExpandBottomRange(n)));
     apiClient
       .get(lineRequestUrl)
@@ -90,6 +90,9 @@ class DiffExpander {
 
   expandHunkAtHead = (n: number, lines: string[], callback: (newFile: File) => void) => {
     const hunk = this.file.hunks[n];
+    if (lines[lines.length - 1] === "") {
+      lines.pop();
+    }
     const newChanges: Change[] = [];
     let oldLineNumber = hunk.changes[0].oldLineNumber - lines.length;
     let newLineNumber = hunk.changes[0].newLineNumber - lines.length;
@@ -129,6 +132,9 @@ class DiffExpander {
 
   expandHunkAtBottom = (n: number, lines: string[], callback: (newFile: File) => void) => {
     const hunk = this.file.hunks![n];
+    if (lines[lines.length - 1] === "") {
+      lines.pop();
+    }
     const newChanges = [...hunk.changes];
     let oldLineNumber = newChanges[newChanges.length - 1].oldLineNumber;
     let newLineNumber = newChanges[newChanges.length - 1].newLineNumber;