diff --git a/src/features/vcs/DiffEditor.module.css b/src/features/vcs/DiffEditor.module.css
index 041e32327..859baa65e 100644
--- a/src/features/vcs/DiffEditor.module.css
+++ b/src/features/vcs/DiffEditor.module.css
@@ -184,11 +184,12 @@
 .host :global(.cm-diffHoverRevert) {
   position: absolute;
   right: 8px;
-  top: 0;
+  /* Centre on the first row, including when the editor's line height changes. */
+  top: calc((var(--openidea-editor-line-height, var(--lh-code)) - var(--space-4)) / 2);
   display: inline-flex;
   align-items: center;
   gap: 3px;
-  height: 16px;
+  height: var(--space-4);
   padding: 0 6px;
   border: 1px solid var(--border-strong);
   border-radius: var(--radius-small);
@@ -239,7 +240,8 @@
   border-left: 1px solid var(--border);
   border-right: 1px solid var(--border);
 }
-.host :global(.cm-diffDivider svg) {
+/* Only the band layer: the chevrons inside the arrow buttons are centred by the button's flex box. */
+.host :global(.cm-diffDivider > svg) {
   position: absolute;
   inset: 0;
 }
@@ -281,6 +283,12 @@
 .host :global(.cm-diffDivider button.cm-diffArrow-b-to-a) {
   right: 1px;
 }
+/* With one direction there is no pair to keep apart: the arrow sits in the middle of the divider. */
+.host :global(.cm-diffDivider-lone button.cm-diffArrow) {
+  left: 50%;
+  right: auto;
+  transform: translateX(-50%);
+}
 .host :global(.cm-diffDivider button.cm-diffArrow:hover) {
   color: var(--fg-strong);
   background: transparent;
diff --git a/src/features/vcs/__tests__/diffScroll.test.ts b/src/features/vcs/__tests__/diffScroll.test.ts
index 30bf85a9a..0b6461b59 100644
--- a/src/features/vcs/__tests__/diffScroll.test.ts
+++ b/src/features/vcs/__tests__/diffScroll.test.ts
@@ -3,6 +3,8 @@ import { Chunk, MergeView } from "@codemirror/merge";
 import { Text } from "@codemirror/state";
 import type { EditorView } from "@codemirror/view";
 import { bandAt, bandPath, transferY, UnalignedPanes, type Band } from "../diffScroll";
+import { readFileSync } from "node:fs";
+import { resolve } from "node:path";
 
 const doc = (s: string) => Text.of(s.split("\n"));
 const LINE = 20;
@@ -171,3 +173,43 @@ describe("animated synchronized scrolling", () => {
     }
   });
 });
+
+describe("divider arrows", () => {
+  const dividerOf = (arrows: { toA: boolean; toB: boolean } | undefined) => {
+    const root = document.createElement("div");
+    const wrapper = root.appendChild(document.createElement("div"));
+    const dom = wrapper.appendChild(document.createElement("div"));
+    const view = { dom, scrollDOM: dom.appendChild(document.createElement("div")) } as unknown as EditorView;
+    const controller = new UnalignedPanes({ sync: false, arrows: arrows && { ...arrows, apply: () => {} } });
+    controller.attach({ a: view, b: view, chunks: [] } as unknown as MergeView);
+    const divider = root.querySelector(".cm-diffDivider")!;
+    controller.destroy();
+    return divider;
+  };
+
+  it.each([
+    ["only the right pane is editable", { toA: false, toB: true }, true],
+    ["only the left pane is editable", { toA: true, toB: false }, true],
+    ["both panes are editable", { toA: true, toB: true }, false],
+    ["no pane is editable", { toA: false, toB: false }, false],
+    ["there are no arrows", undefined, false],
+  ])("centres a lone arrow only: %s", (_, arrows, lone) => {
+    expect(dividerOf(arrows).classList.contains("cm-diffDivider-lone")).toBe(lone);
+  });
+});
+
+describe("diff controls in the stylesheet", () => {
+  // jsdom has no layout, so the selectors that decide how the controls are centred are read from the source.
+  const css = readFileSync(resolve(import.meta.dirname, "../DiffEditor.module.css"), "utf8");
+
+  it("lets only the band layer fill the divider, not the chevrons inside the arrow buttons", () => {
+    expect(css).toMatch(/\.cm-diffDivider > svg\)\s*\{[^}]*position: absolute;[^}]*inset: 0;/);
+    expect(css).not.toMatch(/\.cm-diffDivider svg\)/);
+  });
+
+  it("centres the hover Revert button on the line's own height", () => {
+    const rule = css.match(/\.cm-diffHoverRevert\)\s*\{([^}]*)\}/)![1]!;
+    expect(rule).toContain("top: calc((var(--openidea-editor-line-height, var(--lh-code)) - var(--space-4)) / 2);");
+    expect(rule).not.toMatch(/top: 0;/);
+  });
+});
diff --git a/src/features/vcs/diffScroll.ts b/src/features/vcs/diffScroll.ts
index 7afcf536b..c44fff902 100644
--- a/src/features/vcs/diffScroll.ts
+++ b/src/features/vcs/diffScroll.ts
@@ -175,6 +175,8 @@ export class UnalignedPanes {
     this.sync = opts.sync;
     this.extension = [gapMarks, changedLineGutters, EditorView.updateListener.of(() => this.schedule())];
     this.divider.className = "cm-diffDivider";
+    // A lone arrow is centred in the divider; a pair keeps to the two edges.
+    this.divider.classList.toggle("cm-diffDivider-lone", !!opts.arrows && opts.arrows.toA !== opts.arrows.toB);
     this.divider.setAttribute("data-wheel-scroll", "");
     this.svg.setAttribute("aria-hidden", "true");
     this.svg.appendChild(this.bandLayer);