diff --git a/packages/diff-view/src/parts/RenderCss/RenderCss.ts b/packages/diff-view/src/parts/RenderCss/RenderCss.ts
index e51fba7..7b65c55 100644
--- a/packages/diff-view/src/parts/RenderCss/RenderCss.ts
+++ b/packages/diff-view/src/parts/RenderCss/RenderCss.ts
@@ -220,6 +220,7 @@ export const renderCss = (oldState: DiffViewState, newState: DiffViewState): any
 .DiffEditorContentRight {
   align-items: stretch;
   display: flex;
+  flex: none !important;
   min-height: 0;
   min-width: 0;
   overflow: hidden;
@@ -509,9 +510,6 @@ ${getEmptyLineNumberCss(newState.visibleLinesLeft, newState.visibleLinesRight, i
 }
 
 
-.DiffEditorContent {
-  flex: unset !important
-}
 `
   return [ViewletCommand.SetCss, id, css]
 }
diff --git a/packages/diff-view/test/RenderCss.test.ts b/packages/diff-view/test/RenderCss.test.ts
index 6e851b3..9f42384 100644
--- a/packages/diff-view/test/RenderCss.test.ts
+++ b/packages/diff-view/test/RenderCss.test.ts
@@ -60,8 +60,9 @@ test('renderCss renders left and right widths as css variables', (): void => {
   expect(result[2]).toContain('.DiffEditorContentLeft {')
   expect(result[2]).toContain('.DiffEditorContentRight {')
   expect(result[2]).toContain(
-    '.DiffEditorContentLeft,\n.DiffEditorContentRight {\n  align-items: stretch;\n  display: flex;\n  min-height: 0;\n  min-width: 0;\n  overflow: hidden;\n  position: relative;\n}',
+    '.DiffEditorContentLeft,\n.DiffEditorContentRight {\n  align-items: stretch;\n  display: flex;\n  flex: none !important;\n  min-height: 0;\n  min-width: 0;\n  overflow: hidden;\n  position: relative;\n}',
   )
+  expect(result[2]).not.toContain('.DiffEditorContent {\n  flex: unset !important')
   expect(result[2]).toContain('user-select: text;')
   expect(result[2]).toContain(
     '.DiffEditorRows {\n  background: var(--DiffBackground);\n  contain: layout paint style;\n  cursor: text;\n  flex: 1 1 auto;\n  font-family: var(--DiffFontFamily, monospace);\n  height: 100%;\n  min-width: 0;\n  overflow: hidden;\n}',
diff --git a/packages/e2e/src/diff.pane-flex-sizing.ts b/packages/e2e/src/diff.pane-flex-sizing.ts
new file mode 100644
index 0000000..8e182af
--- /dev/null
+++ b/packages/e2e/src/diff.pane-flex-sizing.ts
@@ -0,0 +1,19 @@
+import type { Test } from '@lvce-editor/test-with-playwright'
+
+export const name = 'diff.pane-flex-sizing'
+
+export const test: Test = async ({ DiffView, expect, FileSystem, Locator, Workspace }) => {
+  const tmpDir = await FileSystem.getTmpDir()
+  await FileSystem.writeFile(`${tmpDir}/before.txt`, 'before')
+  await FileSystem.writeFile(`${tmpDir}/after.txt`, 'after')
+  await Workspace.setPath(tmpDir)
+
+  await DiffView.open(`${tmpDir}/before.txt`, `${tmpDir}/after.txt`)
+
+  const leftPane = Locator('.DiffEditorContentLeft')
+  const rightPane = Locator('.DiffEditorContentRight')
+  await expect(leftPane).toHaveCSS('flex-grow', '0')
+  await expect(leftPane).toHaveCSS('flex-shrink', '0')
+  await expect(rightPane).toHaveCSS('flex-grow', '0')
+  await expect(rightPane).toHaveCSS('flex-shrink', '0')
+}