diff --git a/frontend/src/lib/components/DiffDrawer.svelte b/frontend/src/lib/components/DiffDrawer.svelte
index edb8b1e9dd..01b8c67d1d 100644
--- a/frontend/src/lib/components/DiffDrawer.svelte
+++ b/frontend/src/lib/components/DiffDrawer.svelte
@@ -51,7 +51,8 @@
 				 *  way to tell what their draft is being compared against. */
 				deployedLabel?: string
 				versions?: DiffVersionOption[]
-				onTakeLatest?: () => void | Promise<void>
+				onTakeLatest?: (head?: string) => void | Promise<void>
+				draftBase?: string
 				draft: DiffData | undefined
 				current: DiffData
 				path?: string
@@ -139,12 +140,24 @@
 		}
 	}
 
+	/** The version this drawer presents as the deployed head, when it has a list to say
+	 *  so. Both the action's gate and the base it adopts hang off it, so "take latest"
+	 *  means the version the reader is looking at. */
+	const headShown = $derived.by(() =>
+		data?.mode === 'normal' ? data.versions?.find((v) => v.isHead)?.id : undefined
+	)
+	/** Behind as the drawer can see it: a base that is not the head on display. With no
+	 *  version list there is nothing to compare, so the editor's own gate stands. */
+	const behindShown = $derived.by(
+		() => data?.mode === 'normal' && (headShown == null || data.draftBase !== headShown)
+	)
+
 	let takingLatest = $state(false)
 	async function takeLatest() {
 		if (!data || data.mode !== 'normal' || !data.onTakeLatest || takingLatest) return
 		takingLatest = true
 		try {
-			await data.onTakeLatest()
+			await data.onTakeLatest(headShown)
 			diffViewer?.closeDrawer()
 		} finally {
 			takingLatest = false
@@ -159,7 +172,8 @@
 					deployedLabel?: string
 					versions?: DiffVersionOption[]
 					loadVersion?: (id: string) => Promise<Value | undefined>
-					onTakeLatest?: () => void | Promise<void>
+					onTakeLatest?: (head?: string) => void | Promise<void>
+					draftBase?: string
 					draft?: Value | undefined
 					current: Value
 					defaultDiffType?: 'deployed' | 'draft'
@@ -180,6 +194,7 @@
 				versions,
 				loadVersion,
 				onTakeLatest,
+				draftBase,
 				draft,
 				current,
 				button
@@ -197,6 +212,7 @@
 				deployedLabel,
 				versions,
 				onTakeLatest,
+				draftBase,
 				draft: draft ? prepareDiff(draft) : undefined,
 				current: prepareDiff(current),
 				path: draft?.path || deployed?.path,
@@ -333,7 +349,7 @@
 			{/if}
 		</div>
 		{#snippet actions()}
-			{#if data?.mode === 'normal' && data.onTakeLatest}
+			{#if data?.mode === 'normal' && data.onTakeLatest && behindShown}
 				<Button unifiedSize="sm" variant="default" loading={takingLatest} onClick={takeLatest}>
 					Take latest, keep my edits
 				</Button>
diff --git a/frontend/src/lib/components/FlowBuilder.svelte b/frontend/src/lib/components/FlowBuilder.svelte
index 3f5d8bc87c..668135db37 100644
--- a/frontend/src/lib/components/FlowBuilder.svelte
+++ b/frontend/src/lib/components/FlowBuilder.svelte
@@ -1175,6 +1175,7 @@
 			deployedLabel,
 			versions: await deployedVersionOptions(),
 			onTakeLatest,
+			draftBase: draftBaseVersion,
 			loadVersion: async (id) => {
 				const v = await FlowService.getFlowVersion({
 					workspace: opWorkspace!,
diff --git a/frontend/src/lib/components/ScriptBuilder.svelte b/frontend/src/lib/components/ScriptBuilder.svelte
index c435baf18a..91b81b2d22 100644
--- a/frontend/src/lib/components/ScriptBuilder.svelte
+++ b/frontend/src/lib/components/ScriptBuilder.svelte
@@ -120,6 +120,7 @@
 		initialPath = $bindable(''),
 		userDraftPath = '',
 		onTakeLatest = undefined,
+		draftBaseHash = undefined,
 		autosaveWorkspace = undefined,
 		autosavePath = undefined,
 		template = $bindable('script'),
@@ -898,6 +899,7 @@
 			deployedLabel: deployedVersionLabel(deployed),
 			versions: await deployedVersionOptions(headHash),
 			onTakeLatest,
+			draftBase: draftBaseHash,
 			loadVersion: async (hash) => {
 				const v = await ScriptService.getScriptByHash({ workspace: opWorkspace!, hash })
 				return replaceFalseWithUndefined({
diff --git a/frontend/src/lib/components/diff_drawer.ts b/frontend/src/lib/components/diff_drawer.ts
index 60a125ec0b..fd3222f8f9 100644
--- a/frontend/src/lib/components/diff_drawer.ts
+++ b/frontend/src/lib/components/diff_drawer.ts
@@ -27,10 +27,14 @@ export type DiffDrawerDiff =
 			/** Loads one version's payload. Returning `undefined` leaves the current
 			 *  comparison in place rather than blanking the diff. */
 			loadVersion?: (id: string) => Promise<Value | undefined>
-			/** Moves the draft's base to the head and keeps its content. Passed only
-			 *  while the draft is behind; rendered as a header action so the user
-			 *  takes the latest with the diff in front of them. */
-			onTakeLatest?: () => void | Promise<void>
+			/** Moves the draft's base to the head and keeps its content, rendered as a
+			 *  header action so the user takes the latest with the diff in front of them.
+			 *  Called with the version the drawer is showing as head (from `versions`), so
+			 *  the base adopted is the one the reader just looked at. */
+			onTakeLatest?: (head?: string) => void | Promise<void>
+			/** The version the draft forked from. The drawer offers `onTakeLatest` only
+			 *  while it differs from the head on display. */
+			draftBase?: string
 			draft?: Value | undefined
 			current: Value
 			defaultDiffType?: 'deployed' | 'draft'
diff --git a/frontend/src/lib/components/raw_apps/RawAppEditor.svelte b/frontend/src/lib/components/raw_apps/RawAppEditor.svelte
index cf36d11a62..aec049e8cf 100644
--- a/frontend/src/lib/components/raw_apps/RawAppEditor.svelte
+++ b/frontend/src/lib/components/raw_apps/RawAppEditor.svelte
@@ -139,7 +139,9 @@
 		version?: number | undefined
 		/** Moves the draft's base to the deployed head and keeps its content;
 		 *  offered in the diff drawer while the draft is behind. */
-		onTakeLatest?: () => void | Promise<void>
+		onTakeLatest?: (head?: string) => void | Promise<void>
+		/** The app_version the draft forked from, threaded to the topbar's diff drawer. */
+		draftBaseVersion?: string | undefined
 		// See ScriptBuilderProps — same indicator semantics.
 		loadedFromDraft?: boolean
 		othersDraftsCount?: number
@@ -213,7 +215,8 @@
 		onSavedNewAppPath,
 		condensedHeader = false,
 		version = undefined,
-		onTakeLatest = undefined
+		onTakeLatest = undefined,
+		draftBaseVersion = undefined
 	}: Props = $props()
 
 	// Workspace this editor operates on: the session's acting workspace when
@@ -2309,6 +2312,7 @@
 		bind:pendingDraftPath
 		{version}
 		{onTakeLatest}
+		{draftBaseVersion}
 		{onRestore}
 		{onSavedNewAppPath}
 		{policy}
diff --git a/frontend/src/lib/components/raw_apps/RawAppEditorHeader.svelte b/frontend/src/lib/components/raw_apps/RawAppEditorHeader.svelte
index 8799df9310..0675c2eb8a 100644
--- a/frontend/src/lib/components/raw_apps/RawAppEditorHeader.svelte
+++ b/frontend/src/lib/components/raw_apps/RawAppEditorHeader.svelte
@@ -111,7 +111,10 @@
 		version?: number | undefined
 		/** Moves the draft's base to the deployed head and keeps its content;
 		 *  offered in the diff drawer while the draft is behind. */
-		onTakeLatest?: () => void | Promise<void>
+		onTakeLatest?: (head?: string) => void | Promise<void>
+		/** The app_version the draft forked from; the drawer offers `onTakeLatest` only
+		 *  while it differs from the head on display. */
+		draftBaseVersion?: string | undefined
 		newApp: boolean
 		newPath?: string
 		/** Initial labels for the app, threaded from the loaded app data. */
@@ -183,6 +186,7 @@
 		savedApp = $bindable(undefined),
 		version = $bindable(undefined),
 		onTakeLatest = undefined,
+		draftBaseVersion = undefined,
 		newApp,
 		newPath = '',
 		labels: initialLabels = undefined,
@@ -460,6 +464,7 @@
 			deployed: deployedValue ?? stripRawAppDiffNoise(savedApp),
 			versions: await deployedVersionOptions(),
 			onTakeLatest,
+			draftBase: draftBaseVersion,
 			loadVersion: async (id) => {
 				const v = await AppService.getAppByVersion({ workspace: opWorkspace!, id: Number(id) })
 				// Same normalization as `syncWithDeployed`, so switching versions doesn't
diff --git a/frontend/src/lib/components/script_builder.ts b/frontend/src/lib/components/script_builder.ts
index cf95dfda5b..c28aad82cc 100644
--- a/frontend/src/lib/components/script_builder.ts
+++ b/frontend/src/lib/components/script_builder.ts
@@ -36,10 +36,13 @@ export interface ScriptBuilderProps {
 	 * stop/restart pair is a no-op on a non-live entry.
 	 */
 	userDraftPath?: string
-	/** Moves the draft's base to the deployed head and keeps its content; offered
-	 *  in the diff drawer while the draft is behind. The route owns it because
-	 *  the base lives in a per-kind field of the value. */
-	onTakeLatest?: () => void | Promise<void>
+	/** Moves the draft's base to the head and keeps its content; offered in the diff
+	 *  drawer while the draft is behind. Called with the version the drawer shows as
+	 *  head. The route owns it because the base lives in a per-kind field of the value. */
+	onTakeLatest?: (head?: string) => void | Promise<void>
+	/** The hash the draft forked from, so the drawer offers `onTakeLatest` only while
+	 *  it differs from the head on display. */
+	draftBaseHash?: string
 	/**
 	 * Workspace + path the AutosaveIndicator watches for sync state. Default
 	 * (undefined) falls back to `$workspaceStore` / `userDraftPath` — the
diff --git a/frontend/src/routes/(root)/(logged)/apps_raw/edit/[...path]/+page.svelte b/frontend/src/routes/(root)/(logged)/apps_raw/edit/[...path]/+page.svelte
index ddf58cda89..c1d512249c 100644
--- a/frontend/src/routes/(root)/(logged)/apps_raw/edit/[...path]/+page.svelte
+++ b/frontend/src/routes/(root)/(logged)/apps_raw/edit/[...path]/+page.svelte
@@ -625,19 +625,20 @@
 				newApp={isNewApp}
 				version={parentVersion ??
 					(deployedHeadVersion != null ? Number(deployedHeadVersion) : undefined)}
-				onTakeLatest={draftBaseVersion &&
-				deployedHeadVersion &&
-				draftBaseVersion !== deployedHeadVersion
-					? async () => {
-							// Re-read rather than trusting the head this page loaded with; see
+				{draftBaseVersion}
+				onTakeLatest={draftBaseVersion
+					? async (shown?: string) => {
+							// The version the drawer showed as head, else a fresh read; see
 							// /scripts/edit.
 							const head =
+								(shown != null ? Number(shown) : undefined) ??
 								(
 									await AppService.getAppLatestVersion({
 										workspace: $workspaceStore!,
 										path: page.params.path ?? ''
 									}).catch(() => undefined)
-								)?.version ?? Number(deployedHeadVersion)
+								)?.version ??
+								Number(deployedHeadVersion)
 							parentVersion = head
 							if (deployedBaseline) deployedBaseline = { ...deployedBaseline, parent_version: head }
 							draftBaseVersion = String(head)
diff --git a/frontend/src/routes/(root)/(logged)/flows/edit/[...path]/+page.svelte b/frontend/src/routes/(root)/(logged)/flows/edit/[...path]/+page.svelte
index 0a7eb66067..5133a70223 100644
--- a/frontend/src/routes/(root)/(logged)/flows/edit/[...path]/+page.svelte
+++ b/frontend/src/routes/(root)/(logged)/flows/edit/[...path]/+page.svelte
@@ -544,17 +544,18 @@
 	</div>
 {:else if renderEditor}
 	<FlowBuilder
-		onTakeLatest={draftBaseVersion && version != null && draftBaseVersion !== String(version)
-			? async () => {
-					// Re-read rather than trusting the head this page loaded with; see
-					// /scripts/edit.
+		onTakeLatest={draftBaseVersion
+			? async (shown?: string) => {
+					// The version the drawer showed as head, else a fresh read; see /scripts/edit.
 					const head =
+						(shown != null ? Number(shown) : undefined) ??
 						(
 							await FlowService.getFlowLatestVersion({
 								workspace: $workspaceStore!,
 								path: flowDraftPath
 							}).catch(() => undefined)
-						)?.id ?? version
+						)?.id ??
+						version
 					if (!draftSync.draft || head == null || !$workspaceStore) return
 					draftSync.draft = { ...draftSync.draft, version_id: head }
 					draftBaseVersion = String(head)
diff --git a/frontend/src/routes/(root)/(logged)/scripts/edit/[...path]/+page.svelte b/frontend/src/routes/(root)/(logged)/scripts/edit/[...path]/+page.svelte
index e9baaa79aa..214595eb51 100644
--- a/frontend/src/routes/(root)/(logged)/scripts/edit/[...path]/+page.svelte
+++ b/frontend/src/routes/(root)/(logged)/scripts/edit/[...path]/+page.svelte
@@ -525,18 +525,21 @@
 		bind:this={scriptBuilder}
 		{initialPath}
 		userDraftPath={draftPath}
-		onTakeLatest={draftBaseHash && deployedHeadHash && draftBaseHash !== deployedHeadHash
-			? async () => {
-					// Re-read rather than trusting the head this page loaded with: taking a
-					// stale one would say the draft is up to date with a version that is not
-					// the latest any more.
+		{draftBaseHash}
+		onTakeLatest={draftBaseHash
+			? async (shown?: string) => {
+					// The version the drawer showed as head, else a fresh read: taking the one
+					// this page loaded with would say the draft is up to date with a version
+					// that is not the latest any more.
 					const head =
+						shown ??
 						(
 							await ScriptService.getScriptLatestVersion({
 								workspace: $workspaceStore!,
 								path: draftPath
 							}).catch(() => undefined)
-						)?.script_hash ?? deployedHeadHash
+						)?.script_hash ??
+						deployedHeadHash
 					if (!draftSync.draft || !head || !$workspaceStore) return
 					draftSync.draft = { ...draftSync.draft, parent_hash: head }
 					// The baseline mirrors the draft's base so an unedited draft still