diff --git a/apps/desktop/src/renderer/routes/_authenticated/_dashboard/v2-workspace/$workspaceId/hooks/usePaneRegistry/components/DiffPane/DiffPane.tsx b/apps/desktop/src/renderer/routes/_authenticated/_dashboard/v2-workspace/$workspaceId/hooks/usePaneRegistry/components/DiffPane/DiffPane.tsx
index 3ccae838bb8..2fc56144335 100644
--- a/apps/desktop/src/renderer/routes/_authenticated/_dashboard/v2-workspace/$workspaceId/hooks/usePaneRegistry/components/DiffPane/DiffPane.tsx
+++ b/apps/desktop/src/renderer/routes/_authenticated/_dashboard/v2-workspace/$workspaceId/hooks/usePaneRegistry/components/DiffPane/DiffPane.tsx
@@ -61,6 +61,10 @@ export function DiffPane({ context, workspaceId, onOpenFile }: DiffPaneProps) {
 		() => new Set(data.collapsedFiles ?? []),
 		[data.collapsedFiles],
 	);
+	const expandedSet = useMemo(
+		() => new Set(data.expandedFiles ?? []),
+		[data.expandedFiles],
+	);
 
 	// Stable callback via refs — identity does not churn as collapsedFiles
 	// updates, so memo'd children can skip re-renders on unrelated toggles.
@@ -80,6 +84,19 @@ export function DiffPane({ context, workspaceId, onOpenFile }: DiffPaneProps) {
 		},
 		[updateData],
 	);
+	const setExpanded = useCallback(
+		(path: string, value: boolean) => {
+			const current = dataRef.current;
+			const expanded = current.expandedFiles ?? [];
+			const has = expanded.includes(path);
+			if (value === has) return;
+			const next = value
+				? [...expanded, path]
+				: expanded.filter((p) => p !== path);
+			updateData({ ...current, expandedFiles: next } as PaneViewerData);
+		},
+		[updateData],
+	);
 
 	if (!isLoading && files.length === 0) {
 		return (
@@ -103,6 +120,8 @@ export function DiffPane({ context, workspaceId, onOpenFile }: DiffPaneProps) {
 					diffStyle={diffStyle}
 					collapsed={collapsedSet.has(file.path)}
 					onSetCollapsed={setCollapsed}
+					expanded={expandedSet.has(file.path)}
+					onSetExpanded={setExpanded}
 					viewed={viewedSet.has(file.path)}
 					onSetViewed={setViewed}
 					onOpenFile={onOpenFile}
diff --git a/apps/desktop/src/renderer/routes/_authenticated/_dashboard/v2-workspace/$workspaceId/hooks/usePaneRegistry/components/DiffPane/components/DiffFileEntry/DiffFileEntry.tsx b/apps/desktop/src/renderer/routes/_authenticated/_dashboard/v2-workspace/$workspaceId/hooks/usePaneRegistry/components/DiffPane/components/DiffFileEntry/DiffFileEntry.tsx
index 86f73da280a..26b25700c50 100644
--- a/apps/desktop/src/renderer/routes/_authenticated/_dashboard/v2-workspace/$workspaceId/hooks/usePaneRegistry/components/DiffPane/components/DiffFileEntry/DiffFileEntry.tsx
+++ b/apps/desktop/src/renderer/routes/_authenticated/_dashboard/v2-workspace/$workspaceId/hooks/usePaneRegistry/components/DiffPane/components/DiffFileEntry/DiffFileEntry.tsx
@@ -33,6 +33,8 @@ interface DiffFileEntryProps {
 	diffStyle: "split" | "unified";
 	collapsed: boolean;
 	onSetCollapsed: (path: string, value: boolean) => void;
+	expanded: boolean;
+	onSetExpanded: (path: string, value: boolean) => void;
 	viewed: boolean;
 	onSetViewed: (path: string, next: boolean) => void;
 	onOpenFile: (path: string, openInNewTab?: boolean) => void;
@@ -45,6 +47,8 @@ export const DiffFileEntry = memo(function DiffFileEntry({
 	diffStyle,
 	collapsed,
 	onSetCollapsed,
+	expanded,
+	onSetExpanded,
 	viewed,
 	onSetViewed,
 	onOpenFile,
@@ -55,9 +59,9 @@ export const DiffFileEntry = memo(function DiffFileEntry({
 	const hasBeenNearRef = useRef(false);
 	if (isNear) hasBeenNearRef.current = true;
 
-	const [showFullDiff, setShowFullDiff] = useState(false);
 	const [expandUnchanged, setExpandUnchanged] = useState(false);
 	const reason = deferReason(file);
+	const showFullDiff = expanded;
 
 	const handleToggleCollapsed = useCallback(
 		() => onSetCollapsed(file.path, !collapsed),
@@ -90,7 +94,10 @@ export const DiffFileEntry = memo(function DiffFileEntry({
 		}
 		onOpenInExternalEditor(file.path);
 	}, [file.status, file.path, onOpenInExternalEditor, showDeletedFileToast]);
-	const handleShowFullDiff = useCallback(() => setShowFullDiff(true), []);
+	const handleShowFullDiff = useCallback(
+		() => onSetExpanded(file.path, true),
+		[onSetExpanded, file.path],
+	);
 	const handleToggleExpandUnchanged = useCallback(
 		() => setExpandUnchanged((prev) => !prev),
 		[],
diff --git a/apps/desktop/src/renderer/routes/_authenticated/_dashboard/v2-workspace/$workspaceId/hooks/useWorkspacePaneOpeners/useWorkspacePaneOpeners.ts b/apps/desktop/src/renderer/routes/_authenticated/_dashboard/v2-workspace/$workspaceId/hooks/useWorkspacePaneOpeners/useWorkspacePaneOpeners.ts
index 955c2de7723..9453e4e5fa6 100644
--- a/apps/desktop/src/renderer/routes/_authenticated/_dashboard/v2-workspace/$workspaceId/hooks/useWorkspacePaneOpeners/useWorkspacePaneOpeners.ts
+++ b/apps/desktop/src/renderer/routes/_authenticated/_dashboard/v2-workspace/$workspaceId/hooks/useWorkspacePaneOpeners/useWorkspacePaneOpeners.ts
@@ -32,6 +32,7 @@ export function useWorkspacePaneOpeners({
 							data: {
 								path: filePath,
 								collapsedFiles: [],
+								expandedFiles: [filePath],
 							} as DiffPaneData,
 						},
 					],
@@ -42,11 +43,18 @@ export function useWorkspacePaneOpeners({
 				for (const pane of Object.values(tab.panes)) {
 					if (pane.kind !== "diff") continue;
 					const prev = pane.data as DiffPaneData;
+					const prevExpanded = prev.expandedFiles ?? [];
 					state.setPaneData({
 						paneId: pane.id,
 						data: {
 							...prev,
 							path: filePath,
+							collapsedFiles: (prev.collapsedFiles ?? []).filter(
+								(p) => p !== filePath,
+							),
+							expandedFiles: prevExpanded.includes(filePath)
+								? prevExpanded
+								: [...prevExpanded, filePath],
 						} as PaneViewerData,
 					});
 					state.setActiveTab(tab.id);
@@ -60,6 +68,7 @@ export function useWorkspacePaneOpeners({
 					data: {
 						path: filePath,
 						collapsedFiles: [],
+						expandedFiles: [filePath],
 					} as DiffPaneData,
 				},
 			});
diff --git a/apps/desktop/src/renderer/routes/_authenticated/_dashboard/v2-workspace/$workspaceId/types.ts b/apps/desktop/src/renderer/routes/_authenticated/_dashboard/v2-workspace/$workspaceId/types.ts
index cd2737cf785..c5ef6e83376 100644
--- a/apps/desktop/src/renderer/routes/_authenticated/_dashboard/v2-workspace/$workspaceId/types.ts
+++ b/apps/desktop/src/renderer/routes/_authenticated/_dashboard/v2-workspace/$workspaceId/types.ts
@@ -44,6 +44,7 @@ export interface DevtoolsPaneData {
 export interface DiffPaneData {
 	path: string;
 	collapsedFiles: string[];
+	expandedFiles?: string[];
 }
 
 export interface CommentPaneData {